AIRCRAFT TECHNOLOGY ASSESSMENT
INTERIM REPORT ON THE
STATUS OF THE GAS TURBINE PROGRAM
December 16,1975
Prepared By:
Richard Munt, Eugene Danielson,
and James Deimen
U.S. ENVIRONMENTAL
PROTECTION AGENCY
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Abstract
This report is a brief summary of the status of the aircraft gas
turbine technology assessment program. It is a compendium of the infor-
mation and technical data received from all organizations, government
and industrial, involved in efforts to reduce aircraft engine exhaust
emissions. The technical data have been reduced and presented in the
format that the EPA intends to use in making its assessment of the
growth of low emissions technology in aircraft gas turbines. This
document is, therefore, only a prelude to the assessment topic in that
actual assessment and recommendation are to be covered in the final
report. The final report will be available mid 1976 following the
evaluation of new information. The information contained herein and the
thrust of the assessment are directed towards compliance with the EPA
1979 standards for newly manufactured engines. Consideration of com-
pliance with the 1981 standards for newly certified engines will be
given in later reports as the technology is advanced.
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Table of Contents
Section Page
1. Introduction 1
2. Summary of Standards and Emissions Performance of
Production Engines 3
3. Programs for Reduction of Engine Emissions 8
4. Low Emissions Technology Concepts 20
5. Summary of Best Demonstrated Control Methods 26
6. Summary of Best Demonstrated Retrofitable Control Methods 29
7. Technology Comparison 31
8. Leadtime Analysis 71
9. References 79
10. Appendix A, Data Bank 81
11. Appendix B, Analysis of the Format of the Standards 109
12. Appendix C, Effects of the Use of Tap Water 110
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Introduction
Section 231 of the Clean Air Act, as amended by Public Law 91-604,
directs the Administrator of the Environmental Protection Agency to:
(1) investigate emissions of air pollutants from aircraft to
determine the extent to which such emissions affect air quality and to
determine the technological feasibility of control, and
(2) establish regulations for the control of emissions from aircraft
or aircraft engines if such control appears warranted in the light of
the investigation referred to above.
Furthermore, the Clean Air Act states that any such regulations can
take effect only after sufficient time has been allowed to permit the
development and application of the requisite technology.
The EPA has complied with both mandates of the Clean Air Act,
first, by publishing a report, "Aircraft Emissions: Impact on Air
Quality and Feasibility of Control," which concluded that the impact on
air quality by aircraft was sufficient to justify control and that such
control was technologically feasible, and second, by promulgating stan-
dards limiting the emissions from aircraft engines. These regulations
have various compliance dates in the future commensurate with the lead-
time then thought to be necessary to develop and apply the necessary
technology.
In keeping with the spirit of the instructions to determine the
technological feasibility of control and to allow sufficient time to
permit the development and application of the technology, the EPA has
established an Aircraft Technology Assessment Program for the purpose of
monitoring the development of the low emissions technology for aircraft
engines, both piston and gas turbine. This program for gas turbines was
begun in July, 1974. In order to make the program as comprehensive as
possible, a request for information was sent to all gas turbine engine
manufacturers on October 1, 1974. Concurrently, contact was made with
all other government agencies which were conducting or supporting relevant
work to ensure that the EPA would stay abreast of their developments.
Through the cooperation of the industry and the several government
agencies working in this area, the EPA has received a considerable
quantity of information from which it expects to assess the status of
aircraft engine low emissions development. The present and future
technology, the necessary leadtime, and the cost of compliance with the
EPA regulations will all be reviewed. Additionally, the EPA expects to
review the format of the regulations to assure that it properly reflects
operational and technical realities (eg., is the admissible pollution
level better normalized by the total impulse or energy over the cycle or
simply by the rated thrust or power?). This document and the succeeding
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final report (pl~:.ued for completion by mid 1976) do not address the
issue of compliance with the 1981 regulations for large, commercial
newly certified gas turbine engines. The status of the requisite tech-
nology is in a development stage and assessment is premature and un-
necessary at this time.
This summary does not investigate the issue of cost of compliance
largely because of the lack of hard information available. An EPA
contractor, Arthur D. Little, Inc., has undertaken an attempt, as a part
of its support effort to the EPA, to develop a data base from which cost
estimates can be made. This work will be reported to the EPA in January,
1976.
This interim report intentionally draws no conclusions and makes no
recommendations, but is rather a compendium of the information gathered
thus far by the EPA, reduced and presented in the manner that the EPA
finds useful in conducting this assessment. The EPA decided that con-
clusions or recommendations would be premature at this time because of
the forthcoming public hearing. This public hearing focuses principally
on the EPA proposed regulation of large in-use aircraft (described in
the Federal Register, Volume 38, Number 136, July 17, 1973, 19050) and
secondarily on the aircraft regulations in general (the notice for the
hearing, Federal Register, Volume 40, Number 216, p. 52082, lists several
topics the EPA is particularly interested in having addressed). It is
expected that this hearing will produce useful information for incorpora-
tion into the assessment program. The reader will find that there are
missing data in many instances despite the quantity of information
received. The EPA is hopeful that many of these gaps will be filled in
prior to the publication of the final report.
The report contains summaries of the emissions performance of
existing gas turbine engines, research and development programs leading
to low emissions, low emissions design concepts and how they operate,
best demonstrated performance of engines, and best demonstrated and
retrofitable (readily capable of installation into existing hardware).
There are also discussions of comparative technology and leadtimes
necessary for compliance with the 1979 regulations for newly manufactured
gas turbine engines.
Aircraft piston engines^ are not covered in this document 'as the
approach to performing the assessment for such engines is different from
that for gas turbine engines reported herein. Also, such an assessment
would be difficult to perform at this time owing to the scarcity of
data. It is presently anticipated, however, that sufficient data will
be compiled in time to include an evaluation of piston engine development
in the final report.
-2-
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Section 2 - Summary of Standards and Emissions
Performance of Production Engines
Tl-ie aircraft emissions standards (40 CFS, part 87, described in FR
Vol. 38, N. 136, July 17, 1973, p. 19088) describe standards for the
emission of unburnt hydrocarbons (HC), carbon monoxide (CO), oxides of
nitrogen (NOx), and visible smoke from aircraft gas turbine engines,
newly manufactured and newly certified. The standards for newly manufac-
tured gas turbine engines go into effect January 1, 1979, a date selected
to allow time for proper development of the requisite technology, while
the more stringent standards for newly certified gas turbine engines go
into effect two years later, January 1, 1981 (As a newly certified
engine would allow more latitude to the designer to incorporate low
emissions features such as catalytic burners or low fuel consumption
engine characteristics, standards for such engines are set commensurately
lower). In addition, there are smoke standards applicable to certain
in-use engines at earlier dates. The standards are directed at the
reduction of aircraft emissions including smoke in the vicinity of major
airports which are in or adjacent to major urban areas wherein aircraft
emissions wilj contribute to the general degradation of the air quality.
In general the standards themselves apply not to the aircraft, but
to the engines. The approach to regulate the engines directly instead
of the aircraft was taken to minimize the enforcement effort as the same
engine is often used in several aircraft applications. Furthermore, all
aircraft in which a given engine might be used have generally similar
flight profiles and hence have similar flight profiles and hence have
similar emissions signatures in the airport environs.
In accordance with the latitude permitted by the Clean Air Act
(1970), EPA found it desirable to establish classes of aircraft and
corresponding engine classes to which different sets of standards would
apply as determined by the technical, economic, and safety constraints
relevant to each class. The classes established are as follows:
Table 2-1 Summary of Aircraft Classes
Class Type Aircraft Application
PIPiston engines Light general
(excluding radials) aviation
P2 Turboprop engines Medium to heavy general
aviation; some commercial
air transport
Ti small turbojet/fan General aviation
engines jet aircraft
-3-
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T2 Large turbojet/fan Commercial subsonic
engines intended transports
for subsonic flight
X3 T4 Special classes Commercial subsonic
applying to specific transports
engines for the
purpose of institu-
ing early smoke
standards
T5 Large turbojet/fan SST
engines intended for
supersonic flight
APU Gas turbine auxiliary Many turbojet/turboprop
power units
Piston engines are not considered in this report.
The specific engines within each class to which this technology
assessment is addressed are listed'in Table 2-II along with their present
emissions levels and production potential after January 1, 1979, the
deadline for compliance for newly manufactured engines.
The emissions are described by an EPA parameter (EPAP) which is
defined in the aircraft standards. Briefly, it is a measure of the
total emission of a particular pollutant produced by an engine over a
typical landing-takeoff (LTD) cycle normalized with respect to the total
impulse (for jet thrust engines) or total energy (for shaft power engines)
produced over that cycle. As such, larger engines are permitted proportionally
larger amounts of total emissions over smaller engines.
Production potential is not usually available in hard figures.
Generally though, the production of all engines can be grouped into four
categories for EPA purposes.
Category Situation
I Engines already out of pro-
duction; engines certain to
be out of production by 1/1/79.
II Engines at or near the end
of their production run by
1/1/79. The few, if any, units
produced after 1/1/79 would
not be sufficient to amortize
the development and certification
cost of a low emissions combustor.
-4-
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Ill Engines in the broad middle
of their production run. It is
possible to amortize the necessary
development and certification costs
over the remaining production.
It is equally possible to consider
a cost-effective retrofit of the
units produced prior to 1/1/79;
there are sufficient units to amortize
that development and certification costs
and to realize significant air
quality gains.
IV Engines beginning their pro-
duction run shortly before or
after the 1/1/79 implement-
ation date. There are insuff-
icient engines built prior to
the deadline to warrant a retro-
fit program.
-5-
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Table 2-11
Emissions Performance - Production Engines
1979 Standard
c 1 JIQS IIL CO ii'Ox Engine
Tl 1.6 9.4 3 7 TFC 731-2
(pounds of pollu- -3
tant/1000 pound-
tarust-l'ours/cycle) JT15D
ALF502U
JT12A
C r700
CJ610
tl45ll
RD401
T2 08 4.3 3.0 JT9J
JT10U
Crfi-u
-50
CF1156
RL 211-22B
-524
Spey-
[IK/511
T3 Sane as T2 JT3U
T4 Same as T2 JTBL
T5 Standards not yet Olynpus
promulgated 593
Baseline Emissions
Production ***
Size
3500-3700 Ibs
2200-2500 Ibs
6.500 Ibs
3000-3300 Ibs
4200-4300 Ibs
2350-2950 Ibs
7,500 Ibs
45,000-
53,000 Ibs
41,033
54,000 Ibs
22,000
24,000 IDS
42,000-
50,000 Ibs
9,900-
12,550 Ibs
17,000-
19,000 Ibs
14,000-
19.000 Ibs
3C.OOO Ibs
Manufacturer*
AiUe search
UALL
Avco-Lycominc
P&WA
GL
OL
Rolls-Royce/
Snecma
Rolls-Royce/
P&WA
Pil/A
PM1A
Rolls P.oyce
GL
GL/Snecna
Rolls Royce
Rolls Koyce
P&UA (Smokey)
(Smokeless)
PM;A
Rolls lloyce/
Snecnia
lie
b 6
4.0
8.65
1.9
9.12
14.69
9
.2
4.8
CO
17.5
15.9
29.74
12.0
Ho
93.93
154.89
52
10.2
13.8
ilOx
5.0
6.1
4.10
4.2
data
2.2
2.74
4
3.6
b.7
.lew engine
3.41
4.26
1.6
Do
6.17
34.2
18
3.9
16 2
10.00
10.81
13.it
data
16.02
40. C
26.2
16 0
67
7.20
7.67
4.4
6.20
7.21
3.U
5.6
7.6
8.9
Sk/Std** after 1/1/79
36.2/40 III
45/40 TH
14.1/43 Itl
20/33 IV
I
24/38 I
44/35 I
III, IV
_+ IV +Predicteo
12/20 HI
5/19
IV
13/21 III
13/19 III
2i/24 IV
/21 III
/20
/30 II, "I
/27
53/none I
16/25
28/30 11, HI
28 HI
* t'bbreviations
UACL- United Aircraft of Canada Limited
P&WA- Pratt & Whitney Aircraft
GE - General Electric
** SK/STD- Smoke level/ Smoke Standard
*** Refer to text for definition of categories
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Table 2-11 continued
Class
APU
Class,
P2
1979 Standard
.1C CO 0- tnaino
0.4 5.0 3.0 (.TCl'SS-gaCi*
(pouncis of pollu-
lanc/1000 horse- tTCP30-9i
power-hour of
power output) GTCP3Ci
(.TCP 165
CTCP660
TSCP700
ST6
1979 Standard
IIC CO ..Ox Lnrinu
49 26 G 12.9 PT6A
(pounds of pollu-
tant/1000 horse- -27
pouer-liours/cyclu)
-41
TI-U31-3
250
50J-D22A
75321A
LTP101
PLT27
Uari
Size
260-290
cshp
Size
5CO-1170
eslip
75 eslip
10S9 eslip
6&5-B40
hP
330-400
IIP
4700
csilp
ItiOO
eslip
6LO
eslip
2000
Slip
1B60-3250
cshp
Manufacturer
AiHcsearcli
AiResearcil
AiRe search
AiP.esearcii
AiB.ni.re,,
AiResearcn
UACL
IKCL
AiT-esearcli
Allison
Allison
Avco-Ly coning
Avco—Ly coming
Avco-Lyconint
Kol Is-Uoycc
Baseline
l.C CO
.20 7.5J
.14 5.26
30 19 83
:WX
5.75
3.71
5 24
sions
Sk/Std
Ll.fi.
No data "
.20 79^
.16 .til
.27 2.G3
Baseline
iiC CO
37.5 53. i
70- 106-
93 121
57.1 44.4
42.43 111.0
97 19 0
2.3 17.3
12.1 34.8
.3 3.1
4.87
6.1)5
4.B3
"
"
Emissions
ilOx Sk/Std
5.9
6.11-
5.B
7.8
4.5b
5 4
6.0
5.3
12.8
17.3/48
n.nw
19. 8/40
30/50
Sb/29
17/37
40/50
U/36
ilo data
Production
after 1/1/79
III
III
III
III
III
III
111
Production
after 1/1/79
111
III
III
III
II, III
III
IV
IV
I
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Section 3 - Programs for Reduction of Engine Emissions
This section summarizes all the programs known to the EPA which
bear upon the compliance of aircraft gas turbine engines with the EPA
regulations. These programs are broken into two categories, engine
related programs and combustor research programs. The former are
directed exclusively towards the 1979 EPA standards and the latter are
applicable to all the standards in general as such programs serve more
to advance understanding than to concoct a specific solution.
Engine Related Programs
Government Sponsored Engine Programs
The government has sponsored and continues to sponsor several
major engine related low emissions combustor development programs.
A summary of these programs is provided in Table 3-1. Research and
development in these programs were conducted by private companies,
and in some cases the company partially funded these programs on a
cost sharing basis.
Industry Sponsored Engine Programs
Most of the manufacturers have initiated programs of their own
to identify and refine the technology necessary to satisfy the 1979
standards. In general two approaches were taken. These were modifica-
tion to current production hardware, and new combustor design concepts.
Again, as indicated above, some of these programs were conducted on a cost
sharing basis with the government. A summary of these programs is
provided in Table II.
-8-
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Tajlc 3-1
Engine Related Prograns - Governnent Sponsored
Agency/Conpany
NASA Lewis/Garrett AiKeseorc.)
(Snail Jet Lngine Program)
Demonstrate combustor technology,
for the ThE 731 engine, whicli is
capable of meeting Tl class stand-
ards.
NASA Lewis/Pratt & Uhitne)
Aircraft (Can-nnnular Projran)
Demonstrate combustor technology,
for the JT80 engine, which is
capable cf Meeting the T4 class
standards.
L.ASA U-wis/uetroit Diesel Allison
(Turboprop Program)
NASA Lewis/Genera 1 Electric
(ECCP)
NASA Leuis/Pratt & Whitney
Aircraft (ECCP)
Arny/Detroit Diesel Allison
Demonstrate conbustor technology.
Cor the 501D-22 engine, which is
capable of meeting the P2 class
standards.
Demonstrate conbustor technology,
for the CF6-50 engine, winch
Is capable of meeting the 1979
T2 class standards.
Demonstrate conbustor technology,
for the JT9D engine, which is
capable of neeting the 1979 T2
class standards.
Develop and demonstrate tech-
nology sufficient to obtain a 50
percent overall reduction in
T63 (class P2) engine emissions
with no increase in any individual
pollutant.
Status
Phase I (combustor screening of
three phases is 70 percent cou-
plete.
The combustor concepts being
screened are
1) modified existing coubustor
;) alrblast system (meets hC
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Table 3-1 continued
Agency/ Company
Ariiiy/Uillians Research
/Garrett AiReseaich
/Prate & Uhitney Aircraft
/AVCO Lycoming
Army/Detroit Diesel Allison
EPA/Garrett AiResearch
Develop new high performance
curboshafc engines with low
emissions. Engine has applica-
tion as turboprop (class P2)
or as an APU.
Refine best designs and concepts
from T63 program aoove and test in
a Model 250-C-20B (class P2)
engine.
Develop full scale engine data
to determine the effects of
ambient conditions on emissions
for the TPE331 (Class P2) and
GTCP85 (APU) engines
Status
Program nearlng completion
kllliams concept - meets standards
AiResearch concept - falls standards
Pratt & Whitney concept - no data
AVCO Lycoming concept - meets standards
Funding/Duration
Unknown
Testing has been completed and
data is in final stages in pre-
paration for report. No data
available.
Testing has been completed and a
final report is being prepared
The emissions standards were
achieved in the TPE331 engine by
rescheduling the fuel flow to
operate only on primary atomizers at
taxi-idle.
293K/FY 74-76 (23 months)
Joint project 170K
TPE331 extension 16K'
FY75-.6UO months)
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Tabic 3-11
Engine Related Proferai.is - Industry Sponsored
Company
Status
Funding/Ouration
Garrett AiKesearcn
Garrett ALResearCii
Develop combustor technology for
the TPE 331 engine which allows
it to neet P2 class standards.
Develop conbustor technology
for fue TFU 731 unuiiit! u'.li<_n
allows it to meet Tl class
standard.
Best concept is rescheduling fuel
flow to operate on the primary
atomizers only at taxi-idle. (Meets
HC, CO, NOx standards)
Best concept demonstrated was
tiie air assisted fuel nozzles.
Un^nown/1973-1974 (2 Years)
Garrett AiT.csearcn
j; Carrett AiResearch
' (Small Jet Engine Program)
Pratt & Whitney Aircraft
Pratt & Whitney Aircraft
(ECCP)
Pratt & Whitnev Aircraft
(Can-Annular program)
Pratt & Whitney Aircraft
Develop combustor technology for
APL's wiiich allow tnem to meet tlie
APU standard.
Denonstraie combustor technology
for the TFE-731 engine, which is
capable of meeting Che Tl class
standards
Develop combustor technology for
che JT9D engine which allows Lt
to meet 1979 T2 class standards.
Demonstrate combustor technology
for tne JT9D engine wlncii is cap-
able of meeting tne 1979 T2 class
standards
Demonstrate conbustor technology
for the JT8D engine which is
capable of meeting tne T6 class
standards.
Develop low smoke conbustor for
JT3D (class T3) engine.
Best concepts demonstrated were:
GTCP 36 - airnlast - meets liC
standard, fails CO and
NOx
GTCP u5 - increased fuel spray
cone angle - meets nC
and CO standard, fails
;.0x
CTCP 30 -(production combuscor -
TSCP 700 fmeets HC and CO stan-
-Vjiard, fails n'Ox
GTCP 660 - production combustor -
meets r,C standard; fails
CO and NOx
See Table I
Cost snared with ix'ASA
Company share unknown
See Table I
Best concept demonstrated was
aerating fuel nozzles combined
witn modified airflow distribution.
(Meets- HC, CO standards)
(Tails NOx standard, unless water
is used )
See Table I
See Table I
Best concept demonstrated combined
delaycu dilution wit.i aerating
fuel nozzles. Tnis concept signi-
ficantly reduced l.C and CO w.nle
increasing TIOx.
(Fails HC, CO, NClx cfiinriarHcl
Unknown/1972-1975 (J Years)
Cost shared with NASA
Company share unnnoun
Cost siiared with NASA
Company share unknown
See Table I
See Table I
Unknown/1963-lu74 (6 Years)
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Table 3-U concinueo
Company
Pracc & Jhilney Aircrafc
United Aircraft: of Canada
United
United Aircraft of Canada
Llnlted
Develop Low crussions combustor
Status
JT12A class Tl engine is expected
to be out of production and tnere-
fore no effort was made to reduce
euissions from it.
The best emissions results were
technology for the PT6A-27 and -41 obtained with the conbustor air-
(ciass P2) engines flow redistributed Results
were
PT6A - 41 - meets liC. CO, and NOx
stanciard
PV6A - 27 - meets CO and [10x stan-
dard, fails iIC
Fund ing/Dura tIons
190K/1S73 (1 Year)
Develop lou enissions couDustor
t*»chnolog* for t'.e J713D (class
11) engines
Reducing the fuel spray cone angle 255K/1971, l'J73 (2 Years)
was the r.rost effective concept
demonstrated was tiie rich primary/
delayed dilution concept.
(Meets HC standards)
(Fails CO, NOx standards)
General Llectric
General Electric
(ECCP)
Detroit Diesel Allison
(Turboprop Engine Program)
Determine the most effective
nethod of reducing emissions in
the CJ610/CF700 (class Tl) engines
Demonstrate conbustor technology
for the CF6-50 engine, which is
capable of nesting the 1979 class
T2 standard.
Demonstrate combustor tecnnology
for tiie 501D-22 engine, wnicn is
capable of meeting the P2 class
standards.
Reducing the fuel spray cone angle Unknown/1973-1974 (2 Years)
was tne most effective concept
demonstrated. Uith this metnod
HC levels were reduced 60 percent
relative to current engine (still
fails to meet standard) while NOx
renamed acceptable (meets stan-
dard) and CO was unchanged (fails
to ireec standard)
See Taole I
See Table I
Cost snared wltn 11ASA
Company share unknown
See Taole I
Cost shared with riASA FY 73-7o
Company share 81k Phase I (13 montns)
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Combustor Research Programs
Government Sponsored Combustor Research Programs
Several non-engine related Combustor development programs have also
been sponsored by the government. These programs include grants to
private industry, research laboratories and universities, and NASA and
Air Force "in-house" programs. A summary of these programs is provided
in Tables III, IV, and V.
Also, the government has sponsored a number of analytical combjstor
modeling studies to support the development of necessary low emissions
technology. These studies have also been conducted by private industry,
research laboratories and universities, and NASA and the Air Force. A
summary of these programs is provided in Tables VI, VII, and VIII.
Industry Sponsored Combustor Research Programs
Although such efforts certainly exist within the industry, the EPA
has no explicit knowledge of them, perhaps because they may be appendages
to larger engine related programs.
-13-
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Table 3-m
Government Sponsored Combustor Development Programs
Private Industry ilon Engine Related
Program/Sponsoring Agency
Investigator
Obiertlve
Status
Augnentor Emissions Reduction
TecnnologyAiASA Lewis
Advanceu Concepts to Reduce JOx
in Aircraft/NASA Lewis
Low riOx Emission Combustor/NASA
Lewis
Full Annular Low i40x Lmission
Conbustor/ilASA Lewis
Fundamental Low Power emission
Study/IIASS Lawis
Combustor Exhaust Odor Intensity
and Character Study/NASA Lewis
Supersonic Cruise Combustor
Pollution Teclmolosy/iJASA Lewis
Advanced, Hign-Tenperature-Rise
Combustor/AMRDL
Low Emission Jet Conbustor/AIiRDL
Low iJOx Emission Conbustor for
Automobile Gas Turbine Engines/
EPA-AAPS
Hydrogen Enrichment for Low
Emission Jet Combustion/
NASA llashinston, D.C.
General Electric
Company
Solar Division of
International Harvester
General Applied Science
Laboratory
Solar Division of
International Harvester
A. D. Little
Pratt & i.'liicney Aircraft
General Liectric
Company
Carrctt AlResearch
Jet Propulsion Labora-
tory
United Aircraft of
Canada United
Jet Propulsion Labora-
tory
Reduce enissions from duct
burning engines
Reciuce iIOx at supersonic
cruise conditions
Demonstrate that preriix concept
will result in low JOx at
supersonic cruise conditions.
Investigate application of jet-
inouceu-circulation conbustor
concept to full annular Combustor
Study advanced concepts for
reducing low power emissions tnat
will permit tiie design of combus-
tors meeting the 1951 standards.
To determine toe intensity of
oiiors of exaaust gases from
various turbojet engines or com-
Dustors at several engine opera-
ting conditions, and to determine
jument ooor intensities at stra-
tegic airport locations.
To investigate combustion concepts
specifically designed for low iIOx
emission at supersonic cruise
operating conditions. Tins is an
dduenuuii to ECCP.
ilinmize iIOx, CO, and I1C ana
snoLe levels lor 2-5 Ib/sec
coribustors at 12-16 atn inlet
pressure
To generate and evaluate uncon-
ventional combustor design con-
cepts.
Develop reduced emission and low
fuel economy automotive gas tur-
bine engine.
Approximately 23 percent
complete
Experimental testing completed.
Report being finalized.
A final report is being prepared.
Single source RFP has oeen
issued.
RFP to be issued by first quarter
CY'76
Program completed.
300* FY 75-76
250.C FY 74-75
78K FY 7«
75K FY 75
4OK FY 76
114K
25.C
FY 7^-73
KY 74-75
Program completed.
Project completed.
Program is 30 percent completed.
Project completed.
200K to
eacn investiga-
tor FY 73-74
415K FY 70-73
Untuiown
248K FY 71-74
Expennentally evaluate tne iij - Currently, experimental evalua- 150t(/year
enricliment concept witn a lesearch tion of tne II,-enrichment concept FY 7J, 74,
combustor. is underway with a research com- 75
bustor utilizing premixed H^/
fuel/air mixtures.
Independent Research and Develop-
ment /DOD
Lngine contractors
with DOD
trivate industry is granted a
limited amount of government fund*.
to conduct independent research
prograus soiiie of winch will sup-
port lot' . Missions studies
bniuiown
-------
Table 3-IV
Government Sponsored fonbnstor Developnent Programs
University Grants
Program/Sponsoring Aj.ency
Investigator
Obiective
Status
Mixing in High-Intensity Combustors/ Prof. R.A. Strelilou
HASA Lewis at University of
Illinois
Flow Proces
NASA Leu-is
in Combustors/
Study of Techniques for Lean
Combustion Systems/.JASA Lewis
Influence of Intensity and Scale
of Turbulence on emission Con-
centrations in the Primary Zone
of a Cas Turbine Combustor/NASA
Lewis
Technology Support/CPA
F. Gould in,
S. Leibovich,
F. Moore at
Cornell University
M. Branch,
A. Oppenheim,
R Sawyer at
University of Califor-
nia, Berl.eLey
Piof. A.A. i.tvitz ac
Northwestern
University
Prof. A.11 Mellor at
Purdue University
To develop means to probe Tne effect of turbulence on
molecular-level ni:.edness in molecular mixing is oeing in-
higii-intensity conbustors vestigated.
Measure and predict velocity and Several experiments in progress
turbulence levels in swirling re-
circulating flows with and without
chemical reactions.
Study combustion processes of fuel Assembly of test equipment, is in
lean, turbulent flames at realis- progress.
tic gas turbine conditions to de-
velop stabilization techniques
and improve idle performance.
To determine the effect of turbu-
lence on emission concentrations
within a prenixed combustor using
gaseous propane as a fuel.
To conduct low emissions researcii
to aid in the developnent of low
emission technology.
Project nas been completed and a
tecnnical report nas been pre-
pared.
Currently, a fuel nozzle scudy is
being conducted.
Slit/year
FY 73, 74,
7a, 76
64tC FY 73
7biC FY 7o
7aK FY 75
73n. FY 76
48K/year
FY 72, 73,
74
33K FY 72
40K FY 73
*OK FY 7<>
OOK FY 7i
-------
Table 3-v
CvaL'iat ion of Techniques for
Pollution Reduction
In-house Cxnaust Enissions
Investigation
Swirl Car Combuscors
Induction Conbustors
Basic Pollution Re
Covcrnncnt Sponsored Conbustor Development Programs
nASA/Air Force
Investigator
..ASA Lewis Research
Center
Status
Reduce emissions fron turbojet
conbustors and reheat burners.
AKAPL
NASA Lewis Research
Center
NASA Lewis Research
Center
Provide limited investigated to
further understanding of aircraft
engine exhaust problems.
Continuing "in-house" effort.
The effect of exnaust gas rc-
circulation was examinee and a
final report is in preparation.
Study of catalytic combustors
was studied and tile report issued.
Altitude emissions of refanned
JT3D was studied and tne report
issued.
Program began April 1975 and
will continue for 3 years.
Develop snort-lengt'.i high per- Continuing "in-house" effort.
formance turbojet engine conbustors
having low levels of exhaust emis-
sions suitable for Mach 3 flight.
Develop a short double-annular
combustors for advanced turbojet
engines.
Task completed FY 74. Reports
on final stage is complete.
H.ASA Lantsley Research a) Study reaction kinetics of NO Continuing "in-.iouse" effort.
Center foruation in fuel ricii systems
behind shock waves
b) Study effort of very high
pressure on t<0x foruation.
c) Study the kinetics of soot
formation and decay using laser
light-scattering techniques.
d) I.Ox formation studies in a
jet-stirred reactor.
Single Coabustor Rig Investigation
of Turbine Engine Exhaust Emis-
sions
AFAPL
To investigate novel control and
measurement techniques.
Continuing "in-nouse" effort.
250V. FY 7J
19ik FY 74
50K FY 75
100K FY 76
Unknown
1
-------
Table 3-VI
Government Sponsored Combustor Modeling Programs
Coobustors Design Criteria
Validatlon/AiRDL
l>evelupr»''nl of d 3-1) lombustor
Flow AnjlySls/AFAPL/FAA
Investigator
Garrett AiResearch
United Technologies
Research Center
Low Power Turbopropulsion Combustor Pratt & Whitney Air-
Eoussions/AFAPL craft
Combustor Flow Analysis Procedure
AFAPL/FAA
Analysis and Investigation of
Exhaust Emissions from uon-
Afterburning Aircraft Cas
Tuibine Engines During liign
Pourer/AFAPL
Turbojet Combustor Pollution
Fornation/NASA Lewis
Analysis of Combustion Systems
with Suirl/rtASA Lewis
United Aircraft
Research Laboratory
Pratt & Whitney Air-
craft
General Applied
Science Laboratory
Advanced Technical
Laboratory
Pr wate Industry
Objective
Develop ano validate existing
analytical combustor design
procedures vnicli can be used
co significantly shorten the
design tine of 2-5 Ib/sec. con-
bustors.
To Modify and extend an existing
three-dimensional Navier-stokes
calculation procedure which in-
cludes the effects of chemical
reaction, turbulence transport,
radiation energy flux, and
droplet burning, and vaporisation.
To identify and develop improved
component design techniques which
will increase part-power per-
fornance.
To refine an existing analytical
technique and develop a computa-
tional procedure for predicting
combustion system performance.
Optimize design features through
insight gained from analytical
nodeling of the Combustor at
low power and from experimental
results.
Develop a modular computer program Project completed.
to describe the coupled flow and
combustion kinetics in a turbojet
conbustor.
Preliminary version of computer
program is operational.
Program is approximately 70
percent completed.
Project completed.
Project completed.
Project completed.
Perform numerical modeling of
swirling Clows using finite
difference techniques for pre-
dicting the effect of swirl on
Combustor performance and emis-
sions.
Project completed.
25n. FY 74
aiu. tY 75
100K Fl 71
600K n 72
315K FY 73
177.6K FY 74
S5.dk FY 72
75*. rY 7J
25it FY 74
501v FY Ti
19.5K FY 73
84K FY 71-73
-------
Table 3-VIl
Government Sponsored Coubustor Uodelmc Programs
Univer Grants
Progran
Invest ic.a tor
Objective
Status
Study of Air Pollution from
AircraftAJASA Lewis
Scudy of Parameters Affecting
Emissions of Gas-Turbine
Engines/imSA Lewis
Basic Chemistry of Aircraft
Pollut.ants/:iASA Lewis
John C. i ley wood at
MIT
Prof C M. kiuffnan
University of
Cincinnati
Prof« ssor \. Berlad
SL'N'i-Stonybrook
To predict itOx anu CO levels in
cornbustors and to investigate
fuel atomzation, fuel vaporiza-
tion, and tne mixing process in-
side the conbustor.
Analyze conbustor emission data
and formulate a nathematical
expression tnat correlates
neasureu emissions with prinary
operating conaitions.
Survey current reaction rate
literature on cher.iical reaction
affecting atmospheric ozone
levels, establisn analytical model
of ozone balance in the atmosphere,
and indicate required experimental
rate data needed to solve model.
Continuing research effort.
Data in process of being
analyzed.
Project completed.
66K FY 74
1<)A. FY 75
115k FY 76
33k FY 75-76
4UK FY 73-75
-------
Turbine Engine Exhaust Emissions
Technology
Aircraft Engine Enissions Cor-
relation Technique
Three Dimensional Combustion
Flow Analysis
Combustor Analytical Modeling
of Pollution Formation
Table 3-VI11
Government Sponsored Conoustor Modeling Programs
w\SA/Air Force
Investieatur
AFAPL
Air Force Weapons
Laboratory
Wright-Patterson AFB
NASA Lewis Research
Center
Develop ambient temperature and
huuidity correction factors for
CO and HC.
To predict CO, KC, and r.'Ox and
particulate emissions indicies
for turbine engines used by the
Air force.
Develop a mathematical model
of the combustion process for
annular and can-annular combustors
To study the effects of mixing
and fuel preparation on the
formation of emissions.
Status
Project completed.
Continuing "in-house" effort.
Project completed.
Project completed.
Funding
40K FY 72-73
2K FY 74-75
5K FY 76
BON FY 72-74
30K FY 74
-------
Section 4
Low Emissions Technology Concepts
Considerable testing of several combustor concepts has been con-
ducted by the engine manufacturers. These efforts have been mainly in
fuel preparation techniques, especially nozzle design and fuel dis-
tribution concepts, and in air distribution techniques. No single
technique tested was effective in simultaneously reducing NOx, HC and CO
over the operating range of an engine to the levels required by the 1979
standards. Some, but not all, of the concepts tested did, however,
demonstrate potential to meet the 1979 standards for a given pollutant.
Reduction of all three emissions to the levels required by the standards
will probably require more than one concept to be designed into a com-
bustor. A summary and discussion of the concepts tested is presented
below.
Although often simple in concept, many of these control techniques
are nonetheless difficult to apply in practice. Often, techniques which
involve combustor modification are detrimental to the combustor perfor-
mance in non-emissions related areas such as altitude relight, durability,
etc. An acceptable design is, therefore, often a compromise between
conflicting goals. While economic goals can be compromised, safety
goals cannot, so usually an emissions control technique is in practice
less effective than its potential.
I. Fuel Preparation
1. Airblast - The pressure differential that exists between the
compressor and the combustor is employed to achieve high velocity air
through a venturi system at the combustor inlet. This high velocity air
is directed towards the fuel injectors to help break up the fuel droplets
and thus eliminates locally rich hot spots. By eliminating the locally
rich hot spots, NOx levels should be reduced. Improved atomization at
intermediate power levels such as approach should lead to reductions in
HC and CO levels, also.
This concept is relatively simple since it requires only the
addition of the venturi tubes, and a corresponding balance of airflow to
maintain the fuel-air ratio. No other hardware systems have to be modified.
Success in NOx reduction by utilizing this technique has varied
among the manufacturers. Results of testing combustors equipped with
airblast fuel nozzles indicate that NOx may even increase as a result of
the better combustion efficiency. At low power the pressure differential
is reduced and hence the pressure differential and the air velocity
around the fuel injectors is reduced. Therefore, the airblast effect on
fuel atomization is not as effective at low power where the bulk of the
HC and CO is formed.
-20-
-------
2. Air-assist - An alternative to the airblast technique is the
air-assist concept. This system is the same as the airblast system
except for the method used in creating the high velocity air around the
fuel injectors. In the air-assist technique compressor air is diverted
and compressed externally, and then discharged around the fuel injectors.
Thus the high velocity airblast effect is maintained at all power levels
especially at idle wherein the airblast technique is ineffectual. This
technique should, therefore, be very effective in reducing HC and CO
emissions at low power and in low pressure ratio engines.
The results of experimental testing of combustors equipped with
air-assist systems indicate that substantial reductions in low power
levels of HC and CO emissions can be achieved with this technique.
However, NOx may increase due to a higher flame temperature.
The use of air assist would have a major impact on aircraft hard-
ware systems because of the requirement to redistribute and compress
externally with auxiliary compressions a part of the compressor airflow.
3. Premix - Fuel and air are mixed in a prechamber prior to
entering the primary combustion zone. This premixing allows combustion
to occur at leaner conditions where NOx formation rates are slower. Ex-
perimental test results indicate that NOx reductions can be achieved
where there is sufficient combustor inlet temperature to vaporize fuel
droplets in the prechamber. This means that this technique is most
applicable to high pressure ratio engines, which produce the required
high combustor inlet temperatures.
With the premix concept careful attention must be given to the
prechamber exit conditions. Exit velocities of the fuel-air mixture
must be high enough at all power levels to prevent flashback which is
very damaging to the liner and the nozzle. Also, in creating a lean
primary zone combustor stability may be a problem leading to altitude
flameout and difficulties in relighting.
The premix concept requires a significant change to the combustor
liner geometry since the premix chamber must be included in the combustor,
In some cases this has led unavoidable to a longer overall combustor and
thus in the combuster outer casing.
4. Fuel Atomization - Pressure atomizer nozzle design changes can
lead to changes in the character of the fuel droplet size distribution.
This in turn affects the evaporation time and strongly influences the
amount of HC left unburned. To a lesser extent, the change in the
evaporation rates affect the local fuel-air mixture ratio and thus, the
local temperature which would likely affect the CO and NOx levels.
-21-
-------
Decreasing the flow number (equal to the fuel flow rate divided
by the injector pressure differential)1reduces the droplet size and in
turn the evaporation time. This results in a hotter local mixture which
consumes the HC and CO. NOx, however, increases. This approach is not
universally profitable, however, as experiments indicate that at low
combustor inlet temperatures, no degree of atomization will improve the
droplet evaporation as there is simply insufficient heat available.
Incorporation of this approach into a hardware system involves
changing the pressure differential across the injector unless combined
with the control technique of fuel sectoring (see below, II-3) as other-
wise the fuel flow rate is fixed at each power setting. Changing the
pressure differential requires only a new set of valves and possibly a
pressure boost in the fuel pump.
II. Fuel Distribution
1. Fuel staging - The combustor is divided into two regions, each
having its own fuel injection system. These are termed the pilot stage
and the main stage. At low power, fuel is supplied only to the pilot
stage, thereby allowing twice the fuel/air ratio that would be possible
if the fuel were distributed throughout the combustor. This mixture is
then able to burn hotter, enhancing the CO to C02 conversion and droplet
evaporation (aiding HC burning).
At high power, the fuel is distributed between the two stages in
such a way so as to minimize the peak temperature. This aids in pre-
venting NOx production. Generally, though, this type of combustor also
incorporates air distribution features (See III below) or fuel preparation
features which further aids low NOx levels. Staging requires two fuel
injection locations and adds to the complexity of the fuel supply system
and the fuel control. The combustor liner is also more complex with
additional cooling and temperature profile problems.
2. Nozzle Design - Pressure atomizer nozzle design changes in-
tended to optimize the fuel spray cone angle, and thus the distribution
of fuel in the primary zone, are relatively easy to incorporate into a
combustor.
Decreasing the angle of a wide angle spray cone reduces wall wetting
which in turn helps to reduce HC. Increasing the angle of a fuel rich
narrow angle spray cone is also effective in reducing HC and CO levels
since more complete combustion results from the better fuel distribution.
An optimum angle must be found empirically.
There is no impact on the system hardware as only the fuel nozzle
is changed and the new one is no more complex than the old.
-22-
-------
3. Fuel Sectoring - Fuel sectoring is a method to improve the
combustion conditions at idle and thereby improve HC and CO emissions.
In essence it is like fuel staging in that fuel is selectively removed
from part of the combustor and injected into another in order to achieve
a desirable fuel/air ratio. Specifically, at idle when the combustor is
burning quite lean and at a low flame temperature, the combustion effi-
ciency is poor, resulting in much HC and CO, because of inadequate heat
to vaporize the fuel and to stimulate the CO ->• C02 reaction. This
problem is resolved by cutting off the fuel entirely to part of the
combustor (usually half, and injecting it with the rest of the fuel into
the remaining part of the combustor. This has two beneficial effects:
(1) the flow number of the nozzle is necessarily reduced, improving
atomization and (2) the fuel/air ratio is increased (richened) so that a
hotter flame exists, improving vaporization of the fuel and enhancing
the CO •*• CO- reaction.
Hardware changes are minimal and involve only replacement of half the
fuel nozzle valves with ones designed to open at a higher pressure. As
such this control technique is particularly attractive for retrofit,
especially in view of its nearly universal usefulness.
III. Air Distribution
1. Lean Primary - The lean primary zone is achieved by introducing
a larger percentage of the total combustor airflow into the primary zone
(where the fuel is injected). This creates a leaner, and therefore,
cooler flame which prevents the formation of NOx by lowering the NZ ->
NO reaction rate. An emissions penalty is paid, however, through increased
CO, a result of the lower temperature quenching the CO -»• CO- reaction:
This tradeoff has been witnessed in experiments. Used by itself, there-
fore, this concept is generally unacceptable. If CO can be controlled
by some other combustor concept, then leaning the primary can be adapted
for NOx reduction.
As with the premix concept discussed above, a lean primary zone is
subject to flame stability problems especially at low powers when the
primary is at its leanest condition. Also, the larger amounts of airflow
into the primary leave less air to be used further down the combustor
for cooling the liner or adjusting the temperature profile into the
turbine. This could lead to durability problems.
2. Rich Primary - Theoretically, reducing the primary airflow in-
creases the local fuel/air ratio and hence the primary zone temperature.
At low power, this is beneficial in that the higher temperature enhances
the CO •* CO- conversion and aids in fuel droplet evaporation, thereby
improving the consumption of HC. NOx may be expected to increase slightly.
At high power, the rich primary is very hot, producing large quantitites
of NOx. If the equivalence ratio is greater than one in the primary
-23-
-------
zone, smoke becomes a problem, requiring complicated air flow patterns
in the secondary and dilution zones to consume it. Very limited results
of testing this combustor concept verify the expected CO reductions and
the ensuing smoke problem.
3. Delayed Dilution - By delaying the introduction of dilution
air, a longer combustion zone at intermediate temperatures is provided.
This increases the residence time of the reactants which allows the CO
to CO^ conversion to approach equilibrium and for unburnt hydrocarbons
to be consumed. The temperature in the intermediate zone should be,
however, low enough so that NOx formation rates are slow. Very limited
test data indicates that CO and HC are reduced, as anticipated, with
only marginal increases in NOx. The difficulty lies in adjusting the
air flow into the intermediate zone properly at all power settings so it
is hot enough for CO consumption, yet cold enough to prevent NOx, and
still achieving flame stability, liner duability, etc.
4. Variable Geometry - Variable geometry provides control of the
primary zone such that stable efficient combustion with minimum emissions
occurs over the complete operating range of the engine. Air enters the
combustor through holes equipped with a mechanism (usually a sliding
ring) that meters the airflow in proportion to the fuel flow. With this
system the primary zone fuel air ratio can be controlled to be stoichio-
metric at idle power for HC and CO reductions, and to be lean (but
stable) at high power for NOx reductions.
Very limited testing with this type of combustor has been conducted
and therefore not much data is available. The data does indicate that
HC and CO can be reduced with the variable geometry combustor. However,
the level of NOx increased slightly, owing to inadequate design.
This system has a number of operational drawbacks, primarily the
reliability of the mechanical system in such a severe environment which
is a safety issue. However, the notion of moving mechanical systems in
severe environments is not new to gas turbines: variable pitch compressor
stators and variable turbine nozzle guide waves do exist.
IV. Improvements in Combustor Operating Conditions
1. Increase in "idle Speed - As engine power is reduced, HC and CO
levels generally increase as a result of lower temperatures and pressures
at the combustor inlet. By increasing the engine speed at idle, therefore,
the levels of HC and CO should be reduced. However, the level of NOx
may increase because of the increased temperature in the combustor. The
increased idle speed is limited on turbofan and turbojet engines by the
capability of the aircraft brake systems as there is an increase in
thrust. This problem does not exist with turboprop (class P2) engines
as the thrust can be held nearly constant by properly varying the propeller
pitch with engine speed. Also, there is an attendant increase in fuel
consumption with increased engine speed.
-24-
-------
2. Airbleed - The use of airbleed is merely a means of increasing
the idle speed, particularly of a jet, without suffering the problems of
increased thrust. The additional power is directed towards compressing
and then dumping extra air instead of towards thrust. However, the use
of airbleed results in increased fuel consumption which offsets some of
the expected reductions in emissions.
3. Increased Combustor Length - Increasing the combustor length
increases the residence time of the reactants. This technique theoreti-
cally reduces the levels of CO and HC by allowing the reactions to
proceed further toward the goal of CO. and H»0. NOx, however, might
increase for the same reason. Results of testing this combustor tech-
nique indicate that the CO and HC levels decreased as expected.
A consideration in using this technique is that the length of the
combustor casing would be increased, a major change in the engine which
is likely to be reflected as a change in the engine length and/or center
of gravity, both of which would affect engine installation.
V. Water Injection - Water injected into the primary zone of the com-
bustor results in a lower primary zone temperature. Test results with
water injection indicated that the lower primary zone temperature in
turn results in a reduction in NOx as a result of the lower N_ •* NO
reaction rate. However if the temperature is reduced too much, an
increase in CO occurs.
The use of water injection presents many problems. The increased
aircraft weight due to the mass of water carried may reduce the useful
payload of the aircraft. (Usually, however, water injection results in
increased thrust, and hence the payload can be increased). Higher fuel
consumption is required to maintain turbine inlet temperatures. Pre-
cautions must be taken to prevent ice formation in the water injection
system for operation at ambient temperatures below the freezing point of
water. Water must be demineralized in order to prevent turbine blade
corrosion and pitting. The use of tap water results in substantial
turbine deterioration and thus compromises safety and engine reliability.
(See Appendix C for results of the use of tap water). Demineralized water
can be very expensive (over $0.30 per gallon) depending upon the location.
Logistics for demineralized water may be a problem also, especially for
those aircraft using smaller fields. This approach should be considered
only if other techniques are unsuccessful in reducing emissions.
-25-
-------
Section 5 - Summary of Best Demonstrated Control Methods
Based upon results of the engine related research programs discussed
in Section 3, the best demonstrated combustor concepts have been listed
in Table 5-1. The criterion used for selecting the best concept was to
determine which came closest to meeting the three emissions levels and
•-he smoke standard. In many cases the level of emissions was estimated
from data supplied to the EPA by the manufacturers. It should be noted
that the concepts listed for each engine may not be the best (in terms
of reducing emissions) for that engine. The concepts listed are the
best demonstrated concepts which were known at the time this report was
written. As some of the data is nearly one year old, it is expected
that further improvements have been made.
A comparison of the results in Table 5-1 to the standards indicates
that the NOx standard was achieved (without water injection) by only 33
percent of the engines listed. The CO and HC standards were achieved by
54 percent and 75 percent of the engines respectively. Therefore, it
appears that the most significant unresolved problem is achieving the
NOx standards without the use of water injection.
-26-
-------
Table 5-1
Bos'- "onlrol. Concent Demonstrated
Level Achieved
CFM56
CF4-6
JT9D
RB211
Class T)
Standard
JT3D
Class T4
Standard
JTBD
Class Tl
Standard
TFE731
ATF3
CJ610
CF700
JT15D
M45H
ALF502D
AFP Class
Standard
CTCPS5
GTCP30
takeoff
Modified PV romhimrnr uirh
sector burning at idle
Double annular
With water injection.
Aerating nozzles with rich
primary
With 7000 Ib/hr water in-
jection
Airflow redistribution
etc'
Smokeless burner can
Aerating nozzles with rich
primary
Alt assist (2 59 ppm).
Estimated with water
inject ion
Reverse flow conbustor
Reduced spray cone angle
Reduced spray cone angle
Rich primary/delayed
dilution & added suirl
to nozzle air assist.
Lean primary zone
Airblast
Increase spray cone angle
Pressure atomizing fuel
nozzles
;(EPAP) CO(EPAP) SOx(EPAP) CatoRoi
0 8
0 28
n in
Expected
0 10
0 62
0 8
18 0
0 8
0 05
1 6
0 I*
5 S
6 1
3 8
0.14
1 2
12 0
0.4
0.07
0 1
4 1
2 96
fi n
to be
2 7
2 8
4 3
26 2
4 3
5 1
9.4
6.0
16.9
155
94
10. 9
8.3
4 2
5
3 7
4.S
3
4 2
4 S
similar Co D/A CF6-50
<3
4 5
2 6
<3 with
H.O
3
5 6
3
7 3
3 4
5.2
3 1
4 1
2 7
Z 2
4.8
3 4
1 9
3
6 2
3 4
B
A
R
B
A
A.B
B
B
B
A
B
^
cj
B
A.B
B.C
B.C
B.C
Comments
HC and CO are considerably under standard.
Has smoke number of 20
Has smoke number of 11
Has smoke number of 28
Values estimated
Water inaction r
is equal to fuel flowrate.
Production combustor
By redesigning fuel nozzles, HC Is reduced 60X.
Levels of NOx are acceotable. Further redesign
is noc practical.
Values estimated from production sampling.
Values estimated Horsenower based on n B.75
Production combustor
-------
Table 5-1 continued
Engine
GTPR36
CTCP36
TSCP700
CTCP560
ST6
Class P2
Standard
TPE331
PT6A-27
PT6A-41
501D
250
LTP101
Concept
Insufficient data to make
estimate
Airblast
Reverse flow combustor
with simplex fuel nozzles
Straight through combustor
with simplex fuel nozzles
Airflow redistribution
Reschedule fuel flow to
operate only on primary
atomizers at taxi-idle
Airflow redistribution.
Airflow redistribution
Premix. airblast fuel
nozzle, variable geometry
Premix combustor
Not known
HC(EPAP)
0
0
0
0
4
2
6
1
1
3
30
09
.16
20
20
.9
.0
2
8
.6
5
5
C0(
7
0
7
0
26
14
21
16
4
39
5
EPAP)
.7
8
9
.99
8
.8
9
.6
0
7
.1
10*
5
6
4
6
12
9
8
8
6
3
6
(EPAP) Cnreeory
.4 B,C
0 B
9 B
0 B
9
9 A.B.C
.5 B
3 A,B
.1 A,B
6 B
5 B
AiResearch claims CO standard is achieved
Values estimated from rig test results and
max horsepower point in data
Production combustor
Production combustor
Best results were achieved at 65% rated speed
and 5* rated power.
Values estimated
definition
A - meets gaseous
standard
B - best demonstrated
C - most cost effectiv
-------
Section 6 - Summary of the Best Demonstrated Retrofitable Control Methods
One strategy available to the EPA to achieve a substantial reduction
quickly in the contribution of aircraft to the urban air pollution load
is through retrofit regulations wherein existing, in-use engines must be
cleaned up by a certain deadline. Such regulations for smoke are already
promulgated for the JT8D (T4 class) and JT3D (T3 class). The regulation
is already in effect for the T4 class and will go into effect for the
latter January 1, 1978, unless postponed in accordance with the notice
of proposed rulemaking published by EPA on October 29, 1975 (Federal
Register, Volume 40, Number 209, p. 50453). Another such regulation is
pending for large (over 29,000 pounds-thrust) T2 class engines (Federal
Register, Volume 38, Number 136, p. 19050, July 17, 1973). That proposed
regulation would require all such in-use engines to comply by January 1,
1983 with the 1979 standards (HC, CO, NOx, and smoke) for T2 class newly
manufactured engines.
The degree of success the manufacturers are having in attempting to
comply with this future regulation, plus other potential retrofit situations
not yet proposed, are summarized below in Table 6-1. These concepts do
not require extensive combustor liner or engine case modifications and
yet generally produce significant reductions in emissions. They are,
therefore, quite cost effective as well as retrofitable. For five engines
the best concept demonstrated is also the best retrofitable concept
demonstrated. For the remaining four engines listed, however, the
retrofitable concept demonstrated is not the best concept demonstrated,
and thus represents a compromise in achieving low emissions. There were
no retrofitable concepts demonstrated for fourteen of the engines which
appear in Table 5-1 and so they do not appear in the table here.
-29-
-------
Class Tl
Standard
TFE731
CTCP85
GTCP36
Tai.lc 6-1
Best llL-LroCiLablc Control Concept Ucnonstiateci
Level Achieved
Production combustor with
180° sector burning at idle
Production combustor with
sector burning at idle
B/M burner with aerating
nozzles
20% airbleed at taxi-idle
Reduced spray cone angle
Reduced spray cone angle
Reschedule fuel flow to
operate only on primary
atomizers at taM-idlc
Increase spray cone angle Q 066
Airblast
[EPAP)
0
1
2
I
I
3
3
4
2
0
0
8
63
1
2
A
8
1
8
9
03
4
066
04
CO(CPAP) S'Ox(CPAP) Catefiory Comments
4 3
(. 63
13.3
3 8
9 4
15.3
155
94
26 8
14 8
5
2.6
5 4
7
4
5
3
4
2
2
12
9
3
6
7
74 R
4 R
2 "
fuel consumption.
7 R.B
.2 R'B
and 5X rated thrust.
R.B
7 R,B Production comhuqtor already has airblast
air-assist no77lp.
Definition
R - retrofitable
A - meets gaseous emissions
standards
B - besc demonstrated
-------
Section 7
Technology Comparison
I. There are two general areas of interest covered in this section.
First, an examination of the trends of emissions as functions of certain
engine parameters is presented. This will permit consideration of
questions regarding the structure of the regulations, such as
(1) At what point do small engine characteristics (e.g., lower
pressure ratios) dominate the emissions behavior?
(2) What is the nature of the emissions behavior of small engines?
(3) Is the CO/HC ratio of the standards technically reasonable?
These questions are being asked, but not answered, in this report. The
presentation of the data should cast some light on these issues, however.
To investigate the first two questions, Figures 1 through 12 must
be examined. Figures 1 and 2 show that there is no discernable relation-
ship between the size of an engine and its combustion inefficiency at
idle (the mode of the principal contribution to HC and CO emissions).
This apparently contradicts the argument that the lower pressure ratios
found in small engines (factual, see Figures 3 and 4) and the allegedly
larger surface/volume ratios of the combustors of current small engines
(questionable from Figures 5 and 6) contribute to the poorer emissions
performance of small engines. The combustors of such engines evidently
do perform as well as those of their larger counterparts insofar as
combustion efficiency is concerned.
It is interesting to investigate the explicit effect of pressure
ratio and surface/volume ratio on the combustor performance especially
as the former is functionally related to the engine size (Figure 3).
Figures 7 and 8 show that for all classes of engines, there is no clear,
strong relationship between the combustion efficiency at idle and either
the rated pressure ratio or the actual oressure ratio at idle. While
it is accepted that changes in pressure affect the chemistry within a
combustor, this lack of functional relationship among a population of
engines shows that it is not the pressure ratio alone which determines
the combustor idle emissions performance, but several factors such that
if the pressure is adverse these other factors can be adjusted accordingly
to achieve the desired result. These other factors include the air flow
rate, the temperature, and the combustor volume. These, plus the pressure
ratio, can be combined together into one semi-empirical parameter, the
air loading parameter, which describes the condition of the combustor
with regard to efficiency of combustion. It is, therefore, insufficient
to consider engine emissions as dependent upon the pressure ratio. This
will be discussed in detail later.
The surface to volume ratio, on the other hand, appears to show a
correlation with the idle combustion efficiency (Figure 9). The trend,
however, is hardly conclusive so the addition of data from the many
-31-
-------
engines for which surface/volume data is not available yet to EPA will
be highly useful. As expected, this relationship shows those engines
with higher S/V have, in general, a lower idling efficiency. However,
as mentioned above, Figures 5 and 6 indicate no meaningful correlation
between S/V and engine size, leading to the observation that S/V is not
the basic reason for poor emissions performance in small (or large)
engines.
By considering the whole engine and not simply the combustor per-
formance, it can be seen that the lower pressure ratios (Figure 3) and,
to a much less certain degree, the lower bypass ratios (Figure 10) of
small Tl class engines lead to higher idle specific fuel consumptions
(SFC) (Figure 11). The high SFC, especially at idle, of these small jet
thrust engines is apparently the predominant cause for the higher EPAP
values for HC and CO generally experienced by Tl engines in comparison
with T2 engines. This can be seen more clearly in the following discussion.
The general trend of increasing values of the EPAPs for HC and CO
for decreasing engine size is best seen by considering a weighted sum of
the EPAPs for HC and CO, defined as
Y = .875 EPAP(HC) + 0.2322 EPAP (CO).
As the vast bulk of the HC or CO emissions arise in the idle mode, then
roughly, for instance,
EPAP (HC) - EI(HC)i x Mf (idle)/I
where El. = emissions index at idle (Ibs of pollutant per 1000 Ibs of
fuel), M* = mass of fuel consumed during the mode in question, and I =
total impulse of the engine over the cycle. It then follows that
f = [.875 EI(HC)i + 0.2322 EI(CO),.] x Mf (idle)/I
*
The bracketed term is merely the combustion inefficiency (1 - HC)
times 1000 at idle. The second part, Mf (idle)/I is proportional to the
idle SFC, for
Mf (idle) Mf (idle) 1..^
= x
I I... I
idle
= SFC, .. x Iidle
idle —=—
where the ratio of the idle impulse to the total cycle impulse is roughly
a constant, varying slightly with the manufacturers recommended power
setting for idle. V then is basically proportional to (1 - n ) x SFC
at idle. C
-32-
-------
Figure 12 shows how Y (a weighted sum of the EPAPs for HC and CO)
increases with decreasing engine size. As V is proportional to (1 - n )
x SFC and as it has been seen already that (1 - n ) is not related to
engine size (Figure 1), then obviously the EPAP behavior can be explained
only by the increasing idle SFC with smaller engines (Figure 11), as
claimed above.
While it is historically true that smaller jet thrust engines have
suffered higher SFCs than their larger counterparts, certain data points
on Figure 11 suggest that the most modern of the Tl engines are achieving
SFCs approaching those of the larger modern engines. If that is the
trend in the future, then it would seem that there is no technical basis
for a distinction between the Tl and T2 classes. The only argument that
would favor the retention of a separate Tl class is that the technology
necessary for the T2 class engines to meet their standards is in some
way impractical or perhaps even impossible to incorporate into small
engines. This argument must be assessed carefully, for if it cannot be
substantiated, there may be little need for a separate Tl class.
In comparison, the existence of the P2 class seems to be justified
because; first, the primary output is power, not thrust, and so normaliza-
tion of the cycle pollutants is based on energy (power x time) rather
than impulse (thrust x time) as is the case of the jet thrust type
engines (Tl through TA classes); second, their excellent SFC characteris-
tics would support as technically feasible a separate, more stringent
standard; and third, their capability to operate at higher engine speeds
at idle (more favorable conditions for combustion efficiency and hence
low HC and CO emissions) than jet thrust engines because of their ability
to feather the propeller would make compliance with stronger standards
more likely. Despite all this, it can't be said with certainty that the
P2 class standards are more or less stringent than those for jet thrust
engines for standards with different dimensions (energy vs. impulse)
cannot be readily compared. An obvious possibility, of course, is to
determine the static thrust of a turboprop (P2) engine and propeller
combination, thereby permitting a standardization of the dimensions
among all propulsion classes; pollutants from turboprops would be
presented with respect to impulse instead of energy so that the P2
class standards could follow the same format as the jet thrust classes.
Question 3 can be considered in the light of Figures 13 through 17.
Figure 13 shows the relation between the EPAPs for HC and CO for production
engines. Superimposed on the graph are the various standards with which
these engines will have to comply by 1979. While the T2 class is grouped
in such a way that there is not a good trend line to allow extrapolation
the P2 and Tl class show good trend lines permitting extrapolation.
*
The weighting factor 0.875 is prefixed onto the EI(HC). because the
hydrocarbon emissions index is based on methane (CH.) whereas the fuel
itself has a hydrogen-carbon ratio of about 2.
-33-
-------
Ideally for the designer, the trend line would cross the appropriate
standards "box" at the upper right hand corner. From the Figure, it
appears that for the two classes for which trend lines are established
this Criterion is approximately satisfied. The HC/CO ratio required by
the standards would seem to be reasonable.
Figure 14 shows the actual combustor HC/CO performance (at idle).
There does not appear to be the difference here between the P2 and Tl
classes; in fact all combustors appear to have the same general behavior.
This would suggest that the difference between the EPAP ratios of HC to
CO for the Tl and P2 classes that appears in Figure 13 is due to a
difference in the combustor behaviors of the two classes at some power
setting other than idle, presumably approach. This has, as yet, not
been investigated in detail.
Figure 15 also shows the combustor HC/CO performance at idle, but
now for the advanced combustors which have been developed in attempts to
comply with the EPA aircraft emissions standards. There is considerably
more scatter with these combustors which reflects the increasing diversity
of combustor design.
It is instructive to consider how the HC/CO ratio (or here, the
reciprocal 6 = El(CO)/El(HC)) in the combustor varies with the degree of
combustor inefficiency (Figures 16 and 17). Figure 16 examines production
type combustors, while Figure 17 examines advanced combustors. There is
one notable point to be made here. It is that a few engines show a
counter trend towards a lower B as the inefficiency decreases (Figure 17).
While predominantly P2 class engines, one in this counter trend is a T2
class engine. A consistent pattern of either combustor design or engine
operating mode has not yet been identified to explain this. This phenomenon
cannot be seen in Figure 15 as well (at the lower values of combustion in-
efficiency) because that curve will be directed towards the origin for
decreasing inefficiency for any and all values of 6, thus obscuring
major differences in 6.
-34-
-------
II. The second general area of interest is that of demonstrated or
potential improvements in combustor emissions performance. In general,
compliance with the EPA standards can be achieved by either improvements
in the combustor emissions performance (lower emissions indices) or
improvements in the fuel consumption characteristics (see Appendix B).
However, as compliance with the 1979 standards for newly manufactured
engines generally applies to engines that are already in existence,
there is little that can be done to effect significant improvements in the
fuel economy short of the development of a new engine. This leaves only
improvements in the combustor emissions performance as a means to comply
the 1979 standards. Thus, a review of the combustor development work is
especially important.
Consideration of the emissions will be divided into (1) HC and CO
phenomena and (2) NOx phenomena. To the extent that there is a design
tradeoff between CO and NOx, there will be some overlap.
HC and CO emissions arise from incomplete combustion, primarily at
idle and, to a lesser degree, approach. The extent of incomplete combustion
can be measured quantitatively through the combustion inefficiency,
1-n = .875 *EI(HC) + .2322 *EI(CO) X 10~3
c
where El denotes the emission index. The factor .875 is included in the
hydrocarbon term since the El is expressed in terms of methane (CH.)
whereas the fuel is closer to CH_, the ratio of the molecular weights
being 0.875.
Incomplete combustion results from;
(1) poor fuel preparation (atomization and distribution),
(2) conditions adverse to the evaporation and ignition of the
droplets (low inlet temperature),
(3) inadequate residence time of the flow in the combustor for
completion of the reactions (particularly CO ->- CO- which is quite
slow).
These effects can be described collectively in a single semi-empirical
parameter, the air loading parameter, ft:
where
f(T3)
f(T3) = exp (T3/540)
-35-
-------
The terms in this expression are:
Ha = combustor air mass flow rate (Ib/sec)
P_ = combustor inlet pressure (atmospheres)
V = combustor liner volume (ft )
T~ = combustor inlet temperature (°R)
The expression represents a rough approximation of the extent to
which the fuel combustion should have proceeded. Specifically,
(reaction rate) x (residence time)
Thus, larger values of n mean that the product of the rate times the
time is small, indicating that either the reaction rate or the residence
time or both are small and that, in any case, the reaction cannot have
proceeded very far before the fuel exits the combustor. High values of
combustion inefficiency would then be expected. On the other side of
the coin, smaller values of £1 indicate that the reaction should have
proceeded quite far before the fuel, what is left of it, exits. Low
values of combustion inefficiency would be expected.
A combustor, for any given engine will experience a range of fls
depending upon the power level of the engine, higher power means lower
£2. The actual range of P. from the high power setting to the low will
vary between engines and is dependent upon such design variables as the
compressor pressure ratio, the size of the combustor, and the idle power
setting level. A combustor that is run in a rig test at a simulated
power setting will experience a different fl for that power than in an
actual engine, unless all the inlet conditions are faithfully reproduced.
In any event, the characteristic emissions curve of 1 - n vs f2 will be
generated.
The level of emissions control technology for HC and CO emissions
which are the products of incomplete combustion can then be investigated
systematically by comparing the combustion inefficiency of different
control concepts at equal values of the air loading parameter.
Tigures 18, 19, and 20 show the relationship between the air loading
parameter and the combustion inefficiency for the four principal turbine
classes. Classes T3 and TA are included within the T2 class and APUs
are included within the P2 class. Within each class a definite correlation
is seen between f! and 1-n . There is some scatter, however, which is
systematic, with specific engine lines falling above or below the curve.
It may be inferred in such cases that those engines whose characteristic
air loading parameter vs. combustion inefficiency lines fall above the
mean curve are poorer than average in their emissions performance (HC
and CO).
-36-
-------
It should be emphasized, though, that insofar as HC and CO emissions
are concerned, it is primarily the idle mode (high fl ) that is crucial
(because of the relative emission rates and times in mode at the various
powers). Therefore, the peculiar behavior of the CFM56 at high power in
which its combustion inefficiency does not drop as rapidly as might be
expected is not particularly important as far as HC and CO control is
concerned.
The motivation behind the design of an emissions control scheme is
to lower the characteristic 1-n vs. ft curve of a given engine, primarily
at low power as explained above. The extent to which that line must be
lowered depends upon the fuel economy of the engine, primarily at the
low power modes because the dependence of the EPA parameter on both the
emissions index and the specific fuel consumption (Appendix B). For
example, the Pratt and Whitney JT9D and the General Electric CF6-50,
which are similar with respect to fuel economy, must achieve an idle
combustion inefficiency of about 0.012 (excluding production margins) in
order to meet the HC and CO standards (assuming also that the HC/CO
ratio is correct). This is indicated on Figure 18. Because of the
larger air loading parameter of the CF6-50 at idle, the task is more
difficult, however. Also noteworthy is the excellent combustor HC and
CO emissions performance of the JT8D with its new smokeless can. Unfortu-
nately, its higher SFC implies a very low combustion inefficiency is
necessary in order to meet the standards.
It is instructive to compare the average trend lines of the different
classes. On Figure 20 is superimposed the trends of the Tl and T2
classes onto the P2 and APU trend. It is evident that the different
classes follow different trends indicating that each class has reached
a different level of combustor emissions performance. It must be emphasized,
though, that none of these production combustors have been designed
particularly for low emissions. Other, often conflicting, performance
goals have dictated the design. It is notable, through, that the Tl
class has, in its production engines, the most advanced combustors in
use from the emissions point of view. Actual HC and CO emissions levels
are not better than for the larger T2 class engines, but the performance
is achieved under very adverse conditions of high air loading parameter.
Figure 20 also points out that the APU class engines, even those of
low rated pressure ratio (GTCP85, GTCP660), have HC and CO emissions
performance comparable to the other classes.
Figures 21, 22, and 23 show the combustion inefficiency performance
of the best demonstrated combustors for the various engines. As these
tests were usually run in rigs, not in the engines, the test conditions
and hence, the air loading parameters, were usually not at the engine
values. Nonetheless, the air loading parameter concept permits comparison
between the advanced combustors and the production ones. Superimposed
on each curve are both the trend lines of the production average and the
advanced average for comparison. It is evident that progress has been
made.
-37-
-------
A comparison of the advanced corabustor trend lines shows that, like
the production engines, the Tl class achieves, as a whole, better HC and
CO emissions performance than the other classes. It has only been the
design selection of the combustors (volume) that has led to the very
large air loading parameters at idle and the resulting mediocre combustion
inefficiency. Increasing the combustor volume to lower the air loading
parameter is not usually a practical fix for an existing design as it
is likely to lead to changes in the casing of the engine. Such a change
will increase the residence time in the combustor to help the combustion
of HC and CO; however, this increased residence at high power will
likely lead to additional NOx production.
Both the Tl and T2 classes (including T3 and T4) have apparently
implemented designs which are effective in reducing the combustion
inefficiency at all power levels as the advanced technology trend lines
are low and parallel to those of the respective production trends. For
the P2 and APU classes, on the other hand, the combustion inefficiency
has been noticeably reduced only at the larger air loading values.
While this is acceptable in general for the turboprop (P2) engines
which, because of their excellent specific fuel consumption, are close
to or within compliance limits anyway, it offers little help to the APU
class which is tested only at high power (small air loading value) at
which little improvement in the combustion inefficiency has been demonstrated.
The reasons behind this lack of improvement at high power for the P2 and
APU classes in comparison to the other classes has not yet been explored
in detail.
The emissions performance of a combustor for the oxides of nitrogen
can be evaluated directly by the plot of the emissions index vs. the
combustor inlet temperature (equivalent to the compressor discharge
temperature and, therefore, related to the compressor pressure ratio,
which is an alternative but equivalent presentation). Figures 24, 25,
and 26 present the baseline NOx performance curves for production engines
of the various classes, including APUs. Unlike the emissions performance
for the products of incomplete combustion (HC and CO), all classes
follow the same curve, referred to generally as the Lipfert correlation.
Figure 27 summarizes the preceeding three to demonstrate this. The
correlation is a straight line on a semilog plot indicating, therefore,
that _T
T
El (NOx) <* e °
where here T is 258 °R.
o
The next series of curves, Figures 28, 29, 30, and 31 presents
the NOx emissions performance of the best demonstrated combustors. There
are far fewer data points with which to project accurate trend lines;
however, some observations can be made.
-38-
-------
First, in Figure 28, it appears that fuel staging (CF6-50) is
superior as a NOx control technique than simple improvements to existing
systems as evidenced by the other two engines which utilize a modified
air flow pattern to obtain a rich primary plus an aerating or air blast
type nozzle. This is reasonable as the temperature distribution within
a fuel staged combustor can be better controlled at each power setting
to minimize NOx production without compromising the low CO qualities too
much.
Of course, this number of data points is hardly adequate to draw
definitive conclusions. Further, the preculiar bucket shape of the CF6-
50 profile may be due to erroneous data or due to the flexibility inherent
in the fuel staging concept (to reduce CO at approach, the staging is
set to have a fairly rich, hot primary zone to encourage the CO -»• C02
reaction which has the unfortunate consequence of increasing the NO
production also). A third possibility is that the Lipfert correlation
concept (El(NOx) vs. T_) is inadequate to describe combustor rig data
wherein the high pressures of the high power points cannot, in general,
be simulated. This would affect the NO reaction rate as well as the
residence time. This possibility will be investigated in detail prior
to the final report.
Figure 29 compares the NOx performance of T2 class production
combustors (Figure 24) with that of the few advanced combustors (Figure
28).
Figure 30 suggests, with what data is available, that there has
been no improvement in the NOx emissions characteristics of Tl class
engines, and in fact, a slight degradation in performance is possible at
low powers. However, the data base is totally inadequate to draw con-
clusions: (1) the CF700 already meets the NOx standard so there is no
motivation to improve upon it; (2) the only other two sets of data
points are related concepts applied to the same engine. Substantially
more data is necessary before conclusions can be made. No data for the
TFE 731 is presented as the best demonstrated control technique (all
pollutants) does not involve any modification to the combustor or injector,
but only the application of compressor air bleed at idle. This is
interesting, though, in that at idle it reduces the emissions rate of
all three pollutants.
Figure 31 appears to repeat for the P2 and APU classes the situation
found for the Tl class. Again both the turboprops and the APU behave in
a similar manner and no NOx improvement has been demonstrated. But, as
all P2 engines meet the relevant NOx standard, there is no motivation
for improvement. In fact, in a number of cases, the designers in their
efforts to reduce the HC and CO emissions are willing to increase the
NOx emissions as a tradeoff. The APU engines, on the other hand, all
fail to comply with the NOx standard, including the ST6 which as a °2
class engine (PT6A) meets the P2 standard. It appears that the APUs
will have to develop an as yet unidentified method for NOx control which
exceeds the requirements of the P2 class.
-39-
-------
100,000 ,
IDLE COMBUSTION INEFFICIENCY AS A FUNCTION OF RATED THRUST
PRODUCTION ENGINES
3
X
90.000
80.000
70,000
60.000
50,000
40.000
30,000
20.000
10,000
9000
8000
6000
5000
4000
3000
2000
innn
•
O T2 Class Engines
9 T3 Class Engine:
• T4 Class Engine;
DTI Class Engines
1
0
O
O
a
n
D
a
(
»
I
i
I
0
01
Idle Combustion Inefficiency
Figure 1
-40-
-------
IDLE COMBUSTION INEFFICIENCY AS A FUNCTION OF RATED HORSEPOWER
IU.UUO
7000
Anno
4000
3000
2000
1000
900
800
700
600
SOO
400
300
200
100
O CldS!
O
P2 Engines
O
<
> O
.01 02 03 04 05 06 07 08 09 0.1 2
Idle Combustion Inefficiency
Figure 2
-41-
-------
RATED COMPRESSOR PRESSURE RATIO AS A FUNCTION
OF RATED THRUST,
PRODUCTION ENGINES
30
25
o
at
-------
RATED COMPRESSOR PRESSURE RATIO AS A
FUNCTION OF RATED HORSEPOWER
PRODUCTION ENGINES
o
ot
o
at
£
0.
o
in
in
0)
Q.
O
-------
COMBUSTOR SURFACE TO VOLUME RATIO AS A FUNCTION OF RATED THRUST
PRODUCTION ENGINES
20
—I —
10
9
8
7
TT
o
3
.0
O
U
O
O T2 Class Engines
O T3 Class Engines
• T4 Class Engines
Q Tl Class Engines
10000 20000 30000 40000
Rated Thrust ~»lbs
Figure 5
SOOOO
60000
-44-
-------
COMBUSTOR SURFACE TO VOLUME RATIO AS A
FUNCTION OF RATED HORSEPOWER
PRODUCTION ENGINES
O
ac
0)
_2
O
O
01
O
u
20
9
6
5
4
3
2
O
A
A
O
**
O P2
A APL
Class Engines
Engines
400 800 1200
Rated Horsepower
Figure 6
1600
-45-
-------
IDLE COMBUSTION INEFFICIENCY AS A FUNCTION OF RATED COMPRESSOR PRESSURE RATIO
PRODUCTION ENGINES
u
01
0>
_c
I
JQ
O
JO
T3
on
ft*)
.02
.0
0
a
C
QT2 Class Engines
9T3 Class Engines
TT4- Class ^
ngines
DTI Class Engines
QP2 Class 1
ngines
0
3
D
O
f
0
o
o
C
10 15 20
Rated Compressor Pressure Ratio
Figure 7
25
30
•46-
-------
IDLE COMBUSTION INEFFICIENCY AS A FUNCTION OF IDLE COMPRESSOR PRESSURE RATIO
PRODUCTION ENGINES
fr
S
G
j
_»
•o
in
09
OR
07
06
05
04
01
01
[
<
D
1
a
O T2 Class Engines
O T3 Class Engines
• T4 Class Engines
D Tl Class Engines
O P2C
lass Engines
>
a
O
O
O
•
O
O
0
1 5
2.0 2.5 3.0 3.5
Idle Compressor Pressure Ratio
Figure 8
4.0
-47-
-------
COMBUSTOR SURFACE TO VOLUME RATIO AS A FUNCTION OF IDLE
COMBUSTION INEFFICIENCY
PRODUCTION ENGINES
20
1- •
* °
a
• <;
E 5
3
•5
>
0 4
s
1
" 3
1
•
O Class T2 E
ngines
• Class T3 Engines
• Class T4 Engines
n (.lass 1 1 Engines
O Class P2 E
ngines
D
O
a
a
O
,
O
001 02 03 04 05 .06 07 08 09 01 2
Idle Combstion Inefficiency
Figure 9
•48-
-------
BYPASS RATIO AS A FUNCTION OF RATED THRUST
PRODUCTION ENGINES
o
a.
6
5
3
2
1
0
HD-
Q
D
O
O
O
O
O T2 Class Engines
9 T3 Class Engines
• T4 Class Engines
D Tl Class Engines
3 10000 20000 30000 40000 50000 6000
Rated Thrust ~lbs
Figure 10
-49-
-------
IDLE TSFC AS A FUNCTION OF RATED THRUST
PRODUCTION ENGINES
1.7
1 1
1.0
.9
.8
7
.6
i
•4
D
D
9
O
O T2 Cla
>s Enames
• T3 Class Engines
• T4 Class Engines
nTl Class Engines
O
0
0 10000 20000 30000 40000 50000 60000
Rated Thrust•* Ibs
Figure II
-50-
-------
• AS A FUNCTION OF RATED THRUST
PRODUCTION ENGINES
8
TJ
a
a.
Si
E
3
at
-C
o>
o
50
10
9
8
"3
6
i
i
— D"
a
D
D
H
9
O
O
O
O T2 Cl
« T3 Cl
• T4 Cl
Q Tl Cl
O
ass Engines
ass Engines
ass Engines
ass Engines
0 10000 20000 30000 40000 50000 60000
Rated Thrust ~*lbs
Figure 12
-51-
-------
HC EPAP AS A FUNCTION OF CO EPAP
PRODUCTION ENGINES
100
O
P2 Engines
/\
10
o.
<
PI STANDARD
Tl STANDARD
• Tl Engines
0.1
T2 STANDARD
APU
STANDARD /
O T2 Class Engines
A T3 Class Engines
• T4 Class Engines
a Tl Class Engines
O P2 Class Engines
A APU s
0.1
1.0
10
100
co EPAP
Figure 13
1000
-------
IDLE CO EMISSIONS INDEX AS A FUNCTION OF IDLE HC EMISSIONS INDEX
PRODUCTION ENGINES
160
140
120
o
3
I
Jj)
•o
X
01
•o
c
O
(J
- 100
80
60
40
\
E.
\
20
Combustion
, Inefficiency
1%
\
\
\
o
\
b \
13%
11%
O T2
O T3
• T4
O P2
D Tl
Class Engines
Class Engines
Class Engines
Class Engines
Class Engines
1
\
— 7%
9%
20 40 60
HC Emissions Index at ldle~
80
100
120
1000 Ib fuel
Figure 14
-53-
-------
CO EMISSION INDEX AT IDLE AS A FUNCTION OF HC EMISSIONS INDEX AT IDLE
ADVANCED COMBUSTOR CONCEPTS
160
140
120
£
o
§
TJ
o
x
1
8
too
80
60
40
20
O D
.2-
o
O T2 Class Engines
• T4 Class Engines
O Tl Class Engines
O P2 Class Engines
3%
Combustion
Inefficiency
O
355
6 8 10
HC Emissions Index at Idle **. Ib
lOOOIb fuel
Flgura 15
12
-54-
-------
IDLE El co AS A FUNCTION OF IDLE COMBUSTION INEFFICIENCY
PRODUCTION ENGINES
01
O
7
A
5
4
7
1
9
7
s
•
O T2 Class
0
•ngines
O T3 Class Engines
• T4 Class Engines
D Tl Class Engines
O P2 Class Engines
D°
O
a
a
•
1
O
<
> 0
1
0.01
.02 03 .04 05 .06 .07 .08.09.10
Idle Combustion Inefficiency
Figure 16
-55-
-------
IDLE El ee
ITTc
AS A FUNCTION OF IDLE COMBUSTION INEFFICIENCY
ADVANCED COMBUSTOR CONCEPTS
1000
100
O T2 Class Engines
• T4 Class Engines
Q Tl Class Engines
O p2 Class Engines
CO.
10
O
75—
O
O
O
o.oooi
0 001 0 01
Idle Combustion Inefficiency
Figure 17
0 I
-56-
-------
COMBUSTION INEFFICIENCY AS A FUNCTION OF AIR LOADING PARAMETER
PRODUCTION ENGINES
CLASS T2
10
Approximate level required at
the JT9D and the CF6-SO at idle
010
I
0010
0001
O CF6-50C
9 CF6-6D
• CFM 56
D JT9D-7
LI JT3D-7
• JT8D-17
O RB2II -22
10 1 0
Air Loading Parameter
-------
COMBUSTION INEFFICIENCY AS A FUNCTION OF AIR LOADING PARAMETER
PRODUCTION ENGINES
CLASS Tl
10
010
"a
c
3
-D
O
U
0010
.0001
O CF 700
O M 45H
Q TFE 731
A JT 15D
01
10
Air Loading Parameters Ib
ft3-see
Figure 19
1 0
10
-58-
-------
COMBUSTION INEFFICIENCY AS A FUNCTION OF AIR LOADING PARAMETER
'PRODUCTION ENGINES
CLASS P2 AND APU's
10
010
o
u
0010
0001
7
O 250
Of TPE331
A PT6A-41
Of GTCP660-4
d TSCP700-4
O GTCP85
+ ST6
10
1 0
10
Air Loading Parameter
-------
COMBUSTION INEFFICIENCY AS A FUNCTION OF AIR LOADING PARAMETER
ADVANCED COMBUSTOR CONCEPTS
CLASS T2
010
§
0
1
i
71
£
o
u
0010
0001
O CF6-50C
JT9D-7
• JT8D-17
O RB21I-22
01
Air Loading Parameter **
sec
Figure 21
-60-
-------
COMBUSTION INEFFICIENCY AS A FUNCTION OF AIR LOADING PARAMETER
ADVANCED COMBUSTOR CONCEPTS
CLASS Tl
10
010
Production
Advanced
I
0010
0001
o
O
O CF 700
O M45H
Q TFE 731
A JT15D CONCEPT 1
A JT15D CONCEPT 2
01
10
Air Loading Parameter
1 0
10
Ib
Figure 22
-61-
-------
COMBUSTION INEFFICIENCY AS A FUNCTION OF AIR LOADING PARAMETER
ADVANCED COMBUSTOR CONCEPTS
CLASS P2 AND APLTs
10
010
Production
Advonced
2
o
u
0010
0001
O 250
O TPE331
A PT6A-41
C5 GTCP85
+ ST6
01
10
1 0
10
Air Loading Parameter
Ib
ft'-
Figure 23
-62-
-------
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
PRODUCTION ENGINES
CLASS T2
0)
o
o
o
x
01
-a
c
o
X
O
20
10
4
3
2
i
i
9
./
/
/
/
n •
/
/
/
D
a
a
n/
7
/
.
• /
7
0 C
*/
•
:F6-50C
O CF6-6D
• CFM56
D JT9D-7
[| JT3D-7
• J
T8D-17
600
800
1000
1200
1400
1600
Compressor Discharge Temperature
Figure 24
-63-
-------
O
O
o
X
0)
-o
in
O
X
O
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
PRODUCTION ENGINES
CLASS T1
40
30
20
10
9
8
7
6
5
600
0 CF700
A JT15D
D TFE731
800
1000
1200
1400
1600
Compressor Discharge Temperature
Figure 25
-64-
-------
O
O
o
0)
•g
o
X
o
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
PRODUCTION ENGINES
CLASS P2 AND APU's
in
10
9
;
7
o
A
*/
rf/
s/°
$
/
o
/
Au
£:
0
/
/
0 J
0 5
D 1
A F
cr i
A* c
rf c
-I- ;
(50
•01D22A
PE331
•T6A-41
rSCP700-4
5TCP36
JTCP30
>T6
600
800
1000
1200
1400
1600
Compressor Discharge Temperature **
Figure 26
-65-
-------
NOx EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR DISCHARGE PRESSURE
PRODUCTION ENGINES
o
o
o
O
X
O
40
20
10
9
i
9
O
>
7<
>
/ D
/
f
1
9 •
rV
A/°
A
0
o
y
&/
r/ n
j/W
/o
'oo
Lipfert /
y n
D
0 T2 Cl
/
ass Engines
9 T3 Class Engines
• T4 Class Engines
D Tl Class Engines
A APU Engines
O P2 Class Engines
600
800
1000
1200
1400
1600
Compressor Discharge Temperature*— °R
Figure 27
.66-
-------
0)
o
o
o
X
i
c
o
x
O
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
ADVANCED COMBUSTOR CONCEPTS
CLASS T2
40
30
20
10
9
8
7
6
5
600
D
Production
Advanced
O CF6-50C
D JT9D-7
• JT8D-17
800
1000
1200
1400
1600
Compressor Discharge Temperature *«
Figure 28
-67-
-------
a>
o
o
o
in
O
z
in
x
O
Z
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
PRODUCTION ENGINES AND ADVANCED COMBUSTOR CONCEPTS
CLASS T2
30
20
10
9
8
7
6
5
4
3
2
1
9
*
0
o
o
A
n
o
a
d
OD
o •
9
n
a
o
d
»
0 JT8D PRODUCTION
0 JT8D ADVANCED
0 JT9D PRODUCTION
a JT9D ADVANCED
O CF6-50 PRODUCTION
-------
01
3
o
o
o
x
o
1
(A
O
x
O
40
30
20
10
9
8
7
6
5
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
ADVANCED COMBUSTOR CONCEPTS
CLASS Tl
z
77
/L
O CF700
A JT15D Concept 1
A JT15D Concept 2
600
800
1000
1200
1400
1600
Compressor Discharge Temperature
Figure 30
-69-
-------
40
30
20
0)
o
o
o
X
4)
-O
in
O
X
O
10
9
8
7
6
5
1
.9
NOX EMISSIONS INDEX AS A FUNCTION OF COMPRESSOR
DISCHARGE TEMPERATURE
ADVANCED COMBUTOR CONCEPTS
CLASS P2 AND APU's
Advanced
1L
Production
O 250
D TPE331
A PT6A-41
& GTCP36
<5 GTCP85
4- ST6
600
800
1000
1200
1400
1600
Compressor Discharge Temperature **
Figure 31
-70-
-------
Section 8 - Leadtime Analysis
A peculiar problem exists in the aircraft engine industry, that of
the long delay from identification of technology to incorporation in
aircraft engines. There is now only a three year period before the
regulations become effective and while much work has been accomplished,
primarily to identify what is necessary to satisfy the standards, the
question is raised again whether the industry will be able to comply
with the standards by January 1, 1979.
The time it takes to comply with the standards is readily broken
into two divisions; first, the time necessary to identify the method by
which the emissions will be reduced satisfactorily and second, the time
necessary to incorporate that change into the production hardware.
Schematically,
Requirement -« A •- Technology — B •- Requirement
Specified Identified Satisified
The first period of time, labeled "A", involves "shotgun" experimentation,
parametric experimentation, and possibly analytical studies of sufficient
magnitude and duration to identify a control method which, if refined,
would perform satisfactorily in the application. The second period of
time, labeled "B", involves refinement and optimization of the technology
in rig tests, engine tests, qualification, and introduction into production.
The discussion that follows will consider each of these times separately.
A. Time necessary to identify the requisite technology:
Programs to identify the necessary technology to comply with the
EPA 1979 standards have been carried out on essentially all engines
expected to be in production in 1979. In some instances, the bulk of
the work is directed towards only one member of a family of engines with
the idea that the control technique chosen for that engine will be
appropriate, with only minor adaptations, in other closely related
engines. Baseline emissions testing of the existing production engines
to gauge the magnitude of the problem is done first as a means of sorting
out control concepts which would be totally inadequate. Other concepts
are then selected for screening in rig tests on the basis of their
history of success, if any, convenience to the manufacturer or the user,
and the physical constraints imposed either by the engine itself or its
operating requirements. Totally new and untried concepts may also be
included for general investigative purposes.
"Shotgun" testing of these concepts will identify those which are
unacceptable. The difficulty encountered here is that a design for low
emissions is often contrary to the design for good operational performance
(durability, relight, etc.). These conflicting requirements will render
-71-
-------
some control methods unacceptable and will lead to difficulties in the
perfection of others. Parametric testing is necessary to estimate the
extent to which any given approach can be optimized: The originally
tested version usually has inadequate emissions performance, but often
can be improved in later modifications to satisfy the requirements of
the standards (Task 1, period B, discussion below).
For most engines affected by the 1979 standards, acceptable control
techniques have been identified, at least for HC and CO. The avail-
ability of acceptable NOx control methods is less widespread. Below is
a table (8-1) of the engines and their emission control development status
expressed as future time required to identify acceptable emissions
control techniques. In the cases where an emissions control scheme has
not been identified as yet for a particular engine, an estimate in months
is presented (Time (1), Time (2)), for the additional time required to
complete the screening process for an acceptable solution. As it is
usually NOx control that is causing the roadblock, the second scenario
(Time (2)) is listed wherein it is assumed that the relevant 1979 NOx
standard is raised by 50%. This table must be read with some flexibility,
however. Some of the data from the time estimates-were made are not as
current as other data and more progress has been made in the interim.
Consistent, up to date information on the status of development programs
is needed prior to the final report. These estimates were made by the
EPA and are based upon a review of the best demonstrated technology, the
baseline emissions, the amount of screening done so far, and the problems
peculiar to a given engine (eg., APUs operate at full power with very
low pressure ratios).
Consideration must be given to the few instances, where no satisfactory
resolution of the problem can be identified because the necessary technology
is more sophisticated than can practicably be incorporated into the
engine. The options are then (1) redesign substantial portions of the
engine to allow for the use of other technical approaches not feasible
in the first screening, (2) cease production of the engine, or (3) make
adjustments or exceptions to the regulations. Such a case confronts the
CJ610/CF700 engine family.
-72-
-------
Table 8-1 Lead Time Table
Class Engine Time(l)* Time(2)*
Comment
Tl
T2,T3,T4
P2
APU
TF3A
CF700
CJ610
TFE731
ATF3
JT15D
JT12A
ALF502
M45H
RB401
CF6-6
CF6-50
CFM-56
JT3D
JT8D
JT9D
JT10D
RB211
Spey
TPE331
PT6A
LTP101
250
501
Dart
GTCP36
GTCP30
GTCP85
TSCP700
GTCP660
ST6
-
-
12m
-
12m
-
18m
Om
-
Om
Om
6m
-
-
Om
-
Om
-
Om
Om
6m
Om
Om
-
12m
6m
12m
12m
12m
12m
Om#
Om
12m
Om
Om
Om
6m
12m
Om
Om
Om
Om
6m
Om
Om
12m
Om
6m
Om
12m
6m
No data
Civilian certification uncertain
Will not comply
Will not comply
For time (1) Water injection is likely
No data
Civilian certification uncertain
Will not comply
NOx uncertain
No data
Time (1) requires water injection,
Use CF6-50 technology
Time (1) requires water injection
Time'(l) requires water injection
Will not comply
Not likely to comply without adjustment to
NOx and CO
Time (1) requires water injection
Certification due after 1979
Time (1) requires water injection
No data
Smoke?
Data uncertain
No data
Water injection is not acceptable
(1) Standards as promulgated
(2) NOx standard raised
* Time in months
// "Om" No further time required to identify an acceptable solution
-73-
-------
B. Time necessary to incorporate the low emissions technology into
the production hardware:
Once the technical approach has been identified, it must be effec-
tively implemented into production. The time necessary to achieve this
depends on the accomplishment of the tasks listed in Figures 1 and 2. The
EPA estimates of the time required to complete these tasks are derived
from the times Involved in Phase II and III of the NASA Experimental
Clean Combustor Program, communications with the manufacturers, EPA
experience with smoke reduction programs, and explanations in EPA Report
No. 1168-1, "Assessment of Aircraft Emission Control Technology", September,
1971. The NASA program times are concerned with the demonstration of the
technology in rig and engine prototype tests, while the manufacturer and
EPA times are concerned with engine certification, checkout, and product-
ion preparation times.
Figures 1 and 2 comprise the EPA interpretation of the opinions of
the manufacturers on the often conflicting points of view of the leadtime
issue. On these figures, time starts with the successful identification of
the control technique to be used, that is, the transition from period A
to period B. It must be emphasized that a number of manufacturers are well
beyond the starting point at this time.
The tasks are described as follows:
1. Combustor development and demonstration in rig test. At the
start of this task, a number of low emissions technology concepts have
been applied to a combustor rig and their potential evaluated. Generally
such testing does not yield configurations that are optimized with
respect to emissions and engine performance. In fact, such configura-
tions are often totally unflightworthy as well as perhaps marginal in
emissions performance. Once one or two prospective candidates have been
selected for further development, this task begins.
The chosen concept or concepts must be refined in the rig sufficient-
ly to meet the pertinent standards when applied to the actual engine.
Rig testing also permits extensive optimization of the system for safety
and reliability. It further permits simulated altitude performance
testing (including relight) which otherwise would be very costly in
engine tests in altitude chambers, if possible at all. To proceed
directly to engine testing without this task would be a high risk venture:
The manufacturer would be committed to a design prior to full investigation
of the emissions performance, safety aspects, and operating performance
of the combustor. The time allotted for this task is 15 months for
large engines and 9 months for small ones. For comparison, Phase II of
the NASA Experimental Clean Combustor Program, wherein similar work was
done, was a 15 month effort.
2. Engine Demonstration. Engine demonstration is necessary,
first, to verify that the combustor, which was optimized in the rig
-74-
-------
tests of task 1, operates satifactorily in the full engine, and second,
to design the necessary fuel control system to achieve that satisfactory
performance. Satisfactory performance here means (1) acceptable steady
state performance as evidenced by specific fuel consumption within
production specification and acceptable turbine inlet temperature
profile and (2) acceptable transient performance as evidenced by a
acceleration/deceleration times within FAA requirements with sufficient
surge margin. The time allotted for this effort is 12 to 15 months,
depending on the engine type and the modifications required. For com-
parison, Phase III of the NASA Experimental Clean Combustor Program in
which such work is being performed is 15 months.
3. Production Design and Procurement. This task involves the
design and manufacture (in limited numbers) of all the engine parts
modified by the low emissions system and the associated tooling. Such
engine parts may include, in addition to the combustor liner itself, the
inner and outer casing, diffuser, struts, fuel control, and nozzles.
Manufacturing includes the necessary tooling as well as the limited
production to supply engines for static and flight testing, qualification,
and service evaluation. Proving of the tooling can be accomplished in
parallel with the subsequent steps prior to commitment to production.
As reported in EPA Report No. 1168-1, September, 1971 and by General
Electric in a separate communication this exercise should take a little
over 1 1/2 years, much of which can overlap the engine demonstration
period as the final configuration is finally identified, thereby requiring
only three to four additional months until engine testing can begin.
A. Engine Testing. This activity involves endurance and cyclic
testing necessary first to generate an adequate safety record for later
flight testing and engine qualification and second to develop a main-
tenance and reliability record for service. This is a continuous effort
throughout the service life of the engine, but only eight months are
necessary before sufficient time is accumulated to begin flight tests if
an intensive test schedule is used. In comparison, General Electric
suggested that about fourteen months be given to ground testing before
flight testing begins. Small engines requiring less extensive modification
than the T2 class engines should have less difficulty adhering to this
schedule and, indeed, can probably accomplish the necessary preflight
testing in six months.
5. Flight Testing. This is done primarily to investigate engine
performance at altitude. It is usually done on a corporate owned
experimental aircraft or an available military aircraft neither of which
are subject to the FAA requirements of certification. Included in the
engine performance criteria are thrust, specific fuel consumption,
relight, and transient behavior. Environmental factors such as icing,
etc. may be investigated as necessary. The T2 class engine manufacturers
generally allocate about six months to flight testing prior to start of
-75-
-------
qualification while Tl and P2 class engine manufacturers apparently
often get by with less, perhaps three months.
6. Qualification. This step involves obtaining the necessary type
certificate, supplemental type certificate, or engineering approval for
the low emissions engine. The amount of effort involved here is largely
dependent upon the type of certification necessary. In any case, FAA
certification here involves mostly paperwork as a large part of the
necessary testing has already been done. Following the recommendation
of several of the manufacturers, six months is delegated to this task.
7. Service Evaluation. Once an engine has the necessary FAA
certification or approval, it is, strictly speaking, available for
public use. Nonetheless, another stage of testing, that of service
evaluation, has developed as a matter of industry policy prior to full
production. The procedure in service evaluation is to have a limited
number of engines installed on fleet aircraft (one per plane) for a long
enough period of time to judge their performance, reliability, and
maintainability in actual use. While reliability may be considered a
safety issue (the FAA considers service evaluation a vital supplement to
its own required testing for certification), it is intended primarily to
prove the economics of the engine in service. The length of time of the
service evaluation depends upon the rate at which flight time and landing-
takeoff cycles are accumulated in service and the extent to which the
new system differs from the old (an exotic system will be scrutinized
more thoroughly for reliability). A system which has had a history of
difficulty in development will command a longer service evaluation.
Several manufacturers have indicated that a one year service evalu-
ation would be adequate for their engines. This is a fairly short time,
giving a high time of perhaps 3500 hours and 1400 cycles for commercial
engines and somewhat less for general aviation engines. However, this is
supported by EPA Report No. 1168-1, referenced earlier. It should be
pointed out, on the other hand, that some service evaluations take
longer; for instance, the JT8D and JT3D smoke retrofit programs service
evaluations took 1 1/2 to 2 years to complete. However, both represented
attempts to install advanced technology in quite mature engines (can
and can-annular combustors) and both experienced a history of development
problems.
-76-
-------
EPA Estimate - Tl, P2 classes
Years
1234
Combustor
demonstration
Engine
demonstration
Production
design and
procurement
Engine testing
Flight testing
Qualification
Service
Evaluation
Production
//
//
//
f/>
II
It
'/i
II
II
IL
IL
II
II
'/i
II
77
//
//
//
//
//
//
y/
//
U'
'ii
ii
h
ii
Figure 32
-77-
-------
EPA Estimate - T2, T3, T4 Classes
Years
Combustor
demonstration
Engine
demonstration
Production
design and
procurement
Engine
testing
Flight
testing
Qualification
Service
evaluation
Production
//
'II
II
II
'II
II
II
'/,
'h
II
II
II
II
'h
7/
//
/
h
II
II
II
-------
References
1. Experimental Clean Combustor Program - Phase I Final Report, June 1975,
General Electric Company.
2. Experimental Clean Combustor Program - Contractor Briefing Meeting,
June 12, 1974, General Electric Company.
3. Experimental Clean Combustor Program - Contractor Briefing Meeting,
June 26, 1975, General Electric Company.
4. CF-700/CJ610 Engines - Emissions Reduction Progress Review, August,
1975, General Electric Company.
5. Letter from D.W. Bahr (GE) to E.G. Stork (EPA) dated Feb. 28, 1975
Subject: Pollution Emissions Reductions.
6. Letter from D. W. Bahr (GE) to Richard Munt (EPA) dated Sept. 24, 1975
Subject: Pollution Emissions Reductions.
7. Letter from D.W. Bahr (GE) to Richard Munt (EPA) dated Sept. 29, 1975
Subject: Data on CF6-6D engine.
8. Notes and Summary of EPA/GE Pollutant Emissions Control Technology
Review, July 29, 1975.
9. Experimental Clean Combustor Program Monthly Technical Progress
Narrative & Financial Management Report for Period: 4 August through
31 August 1975, General Electric Company.
10. Experimental Clean Combustor Review, June 12, 1974, Pratt & Whitney
Aircraft.
11. Pollution Technology Program Review, June 26, 1975, Pratt & Whitney
Aircraft.
12. Emission Technology Development at Pratt & Whitney Aircraft, Dec. 17,
1974.
13. Experimental Clean Combustor Program - Phase I Final Report, Oct.
1975, Pratt & Whitney Aircraft Meeting with Pratt & Whitney Aircraft,
July 1, 1975.
14. Aircraft Emission Control Program Status Report, Vol. I and Vol. II,
Dec. 4, 1974, Garrett Corporation.
15. Monthly Technical Progress Narrative No. 9, (Small Jet Aircraft)
Engine Program, Sept. 15, 1975, Garrett Corporation.
-79-
-------
16. Monthly Technical Progress Narrative No. 10, (Small Jet Aircraft
Engine Program), Oct. 10, 1975 Garrett Corporation.
17. USAA MRDL Technical Report 73-6 - Investigation of Aircraft Gas
Turbine Combustor Having Low Mass Emissions, April 1973, Detroit
Diesel Allison.
18. Monthly Technical Progress Narrative No. 8, (Turboprop Engine Program),
Sept. 15, 1975 Detroit Diesel Allison.
19. Monthly Technical Progress Narrative No. 9, (Turboprop Engine Program),
Oct. 15, 1975 Detroit Diesel Allison.
20. Status of Emission Control Development Technology, Nov. 11, 1974,
United Aircraft of Canada.
21. Visit to Rolls-Royce Bristol and Derby by Richard Munt (EPA), May, 1975.
22. Letter from Commanding Officer, Naval Air Propulsion Test Center to
Commanding Officer, Eustis Directorate, U.S. Army Air Mobility Research
and Development Laboratory, Fort Eustis, Virginia dated March 22, 1972
Subject: Army M1PR AMRDL 71-6-T55-L-11A Engine; results of exhaust
emissions tests.
23. Letter from Commanding Officer, Naval Air Propulsion Test Center to
Commanding Officer, Eustis Directorate, U.S. Army Air Mobility Research
and Development Laboratory, Fort Eustis, Virginia dated July 19, 1972
Subject: Army M1PR AMRDL 71-6-T53-L-13A Engine; results exhaust
emissions tests.
24. Proposal: Effects of Ambient Conditions on Aircraft Engine Emissions
by Combustor Rig Testing, May 19, 1975, AVCO Lycoming.
25. Letter from E.J. Sweet (AVCO Lycoming) to Richard Munt (EPA)
dated April 18, 1975.
26. EPA Report No. 1168-1, Assessment of Aircraft Emission Control Technology,
September, 1971.
27. Letter from A.B. Richter (Air Force Logistics Command) to Richard Munt
(EPA), dated May 22, 1975.
-80-
-------
Appendix A
Data Bank
-81-
-------
ENGINE: ALL. 250B15G
V comb: 0.127 ft£
S comb: 1.24 ft
PRODUCTION
T rated: 330 eshp
IT : 6.2
IDLE POWER:
10 % rated
P, T, M
3 3 a
MODE tetra) (°R) (#/S) ft f/a l-nc
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
Prechambei
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
Extended F
IDLE
APPROACH
CLIMBOUT
TAKEOFF
3.03
3.78
5.99
6.28
V=0.
3.03
3.78
5.99
6.28
rimary
730
830
965
985
18 ft3
760
830
965
985
, v=o.
1.87
2.32
3.14
3.22
S=l.
1.85!
2.32
3.14
3.24
zift3
•
.491
.359
.166
.150
64 ft2
.346
.256
.118
.107
, S= 2
.0109
.0124
.0185
.0198
.010S
.0124
.0185
.0196
.53 ft
l
-
.0403
.0158
.0024
.0020
.0050
.0018
.0018
.0014
El
HC CO
20.18
5.18
0.38
0.25
2.00
0.23
0.060
.0436
•
97.35
48.6
9.0
7.83
14.01
7.0
7.4
5.76
NO
X
1.45
2.18
5.95
6.59
1
1.58
3.40
5.52
5.81
•
CO
-------
ENGINE:
V comb:
S comb:
PRODUCTION
All 501D22A
T rated: 4358 eshp
* : 9.7
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
Reverse Flc
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
Prechamber
IDLE
APPROACH
CLIMBOUT
TAKEOFF
Po
J
tetm)
3.64
8.30
9.45
9.70
w Mod
Basel
T3
(°R)
795
1059
1091
1099
ne
M
(///S)
15.0
33.0
33.0
33.0
.
ft
f/a
.0113
.0096
.0185
.0200
825
1281
•
•
l-\
026
0029
0013
0007
.0014
.0009
0007
.0009
.0007
0065
.0010
,OQQ5
HC
17.6
1.96
0.89
0.28
0.61
0.55
0.52
0.77
QJiQ
5.00
0.47
O.Q9
El
CO
43.6
5.10
2.06
2.04
3.88
1.83
1.01
0.95
1.53
9.13
2.64
1.64
N0x
3.53
7.49
9.22
8.88
•
4.Q5
6.48
10.57
10.64
1.86
5.80
11.16
11.23
•
oo
u>
i
-------
ENGINE: TPE331
V comb: .265 ft
S comb: 4.01 ftA
PRODUCTION
T rated: 840 SHP
•a : 10.57
IDLE POWER: 5
% rated
P, T, M
3 3 a
MODE (cjtm) (°R) (#/S) Jl f/a l-nc
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
3.07
9.11
9.99
10.09
3.19
8.86
9.57
9.72
793
1122
1142
1145
797
1123
1140
1142
2.61
7.31
7.15
7.62
3.01
7.38
7.20
7.26
.301
.065
.052
.054
.322
.069
.056
.055
.0119
.0095
.0159
.0167
.0097
.0093
.0152
.0161
-
•
.084
.002
.0004
.0003
.0065
.0017
.0003
.0002
El
HC CO
79.11
.624
.139
.102
2.704
.300
.064
0.20
61.53
6.94
:973
".766
17.612
6.279
1.141
.973
.
NO
X
2.867
9.901
11.851
12.356
4.20S
L0.612
L2.125
12.57]
00
-------
ENGINE: LTP101
V comb:
S comb:
PRODUCTION
T rated: 610 eshp
IT : 8.3
IDLE POWER:
4.6
% rated
MODE
IDLE
2X IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
3.33
4.01
5.03
8.0
8.3
T
3
830
910
935
1059
1078
M
(///S)
2.32
2.78
3.26
4.64
4.78
ft
f/a
.0115
.0114
.0133
.0185
.0195
•
-
l-nc
.030
HC
19.2
El
CO
45
NO
X
•
I
oo
-------
ENGINE: T5321A
V comb:
S comb:
PRODUCTION
T rated: 1,800 eshp
IDLE POWER:
% rated
7T
8.0
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
fctm)
2.6
4.81
7.75
8
T3
(°R>
758
895
1072
1100
M
(*/S)
6.0
9.2
13.9
14.1
•
ft
f/a
.0130
.0148
.0207
.0217
•
•
•
.
L-nc
HC
El
CO
NO
X
•
I
00
ON
-------
ENGINE: T53-L-13A
V comb:
S comb:
PRODUCTION
T rated: 1400 shp
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
(a'tm)
2.38
4.39
7.07
7.3
T3
<°R>
733
868
L040
L066
M
(///S)
4.7
7.2
ID. 8
11.0
ft
f/a
.0130
.0148
.0207
.0217
\
•
1
l-nc
HC
9.52
0.39
-
-
El
CO
33.94
5.97
0.97
0.84
.
N0x
2.71
4.78
7.58
8.23
•
00
-J
I
-------
ENGINE: PT6A-41,
V comb: .26 ft'
S comb: 3.66 ft
PRODUCTION
T rated: eshp
IT : 8.26
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
MOD. A
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
(atm)
2.00
4.89
7.76
3.12
2.16
5.01
8.03
8.42
T3
<°R)
628
837
982
1001
660
867
1005
1017
M
(///S)
3.53
6.39
8.22
8.49
3.72
5.97
8.18
8.46
•
ft
1.219
.300
.128
.118
1.054
.254
.115
.107
f/a
.0116
.0118
.0161
.0168
.0095
.0122
.0166
.0169
ATp
NSP
\
•
•
•
l-nc
.12
.029
.003
.0028
.0563
.0072
.0008
.0007
HC
101.6
22.7
2.02
1.75
35.5
3.39
.32
0.3
•
El
CO
115.3
34.8
6.48
5.06
66.9
14.36
1.55
1.2
•
N0x
1.98
4.65
7. 5b
7.98
•
2.79
6. OB
9.45
10.2
.
•
00
00
-------
ENGINE: GTCP30
V comb:
S comb:
PRODUCTION
T rated: 78RP
3.76
IT :
c
POWER
r, M
3 a
(///S) ft f/a
El
HC
CO N°x
78 HP
ADVANCED :
ADVANCED:
2.42
2.4*
2.52
687
790
794
.947
.-963
.954
.
*
.0198
.0199
.0201
\
•
1
.0014
.0014
.0013
.110
.139
,139
5.576
5.549
5.259
3.506
3.620
3.706
I
00
VD
I
-------
ENGINE: GTCP36-50
V comb:
S comb:
PRODUCTION
T rated: 103 HP
V 3'25
M
El
POWER
ft f/a
l-nc
HC
CO
NO
79 HP
94 HP
103 HP
ADVANCED :
ADVANCED :
3.32
3.47
3.57
Airbls
.997
.997
882
893
906
st
923
926
1.91
1.96
1.88
2.35
1.77
.017
.018
.020
.0113
.0207
-
1
.0057
.0043
.0028
0101
0018
.346
.141
.044
1.042
.041
•
23.066
L7.793
LI. 645
38.88
7.395
•
4.100
4.332
4.253
5.175
5.111
VO
o
-------
ENGINE: GTCP85-98
V comb: -229 ft3/can
S comb: 1-99 ft2/can
PRODUCTION
T rated: 293 HP
TT : 3.36
POWER
243 HP
277 HP
293 HP
ADVANCED :
237 HP
ADVANCED :
-
P3
0»tm)
3.30
3.60
3.74
Wide i
Spray
3.51
3.29
^
(°R)
863
870
876
ngle
cone
1000
990
M
£J
(»/S)
3.97
4.26
4.36
4.21
3.79
R
.409
.370
.350
.301
.310
f/a
.019
.019
.019
.0147
.0178
•
-
l-nc
.0023
.0022
.0020
.0025
.0019
HC
.182
.163
.145
.173
.077
El
CO
9.164
8.87
7.972
9.809
7.876
.
NO
X
5.411
5.593
5.856
5.73
5.780
•
I
VO
-------
ENGINE: TSCP700-4
V comb: .560 ft3
S comb: 4.62 ft2
PRODUCTION
T rated: 772 HP
n : 10.37
M
El
POWER
n
f/a
l-nc
HC
CO
ejy HP
704 HP
772 HP
ADVANCED :
ADVANCED :
6.96
7.16
7.77
992
1001
1028
6.75
7.00
7.29
•
.058
.056
.048
.020
.020
.020
•
-
.0005
.0006
.0005
.183
.244
.189
1.550
1.446
1.328
7.108
7.377
7.806
•
VC
tv:
I
-------
ENGINE: GTCP660-4
V comb: .866 ft3
S comb: 8.23 ft2
PRODUCTION
T rated: 1141 HP
IT : 3.5
P, T, M
3 3 a
POWER (4tm) <°R) (///S) ft f/a l-nc
958 HP
1045 HP
1141 HP
ADVANCED :
ADVANCED:
3.05
3.24
3.40
854
863
870
13.49
1,5.19
15.80
•
.430
.428
.403
.019
.018
.018
•
•
.0025
.0025
.0022
El
HC CO
.224
.400
.305
9.608
8.972
8.349
•
NO
X
4.924
5.119
5.320
VO
l*J
I
-------
ENGINE: CF700-2D
V comb: .607 ft3
S comb: 5i04 fj.2
PRODUCTION
T rated: 4500 Ibs
'n5 6.60
IDLE POWER:
6.24 % rated
MODE
M
(///S) ft f/a
El
l-nc
HC
CO
NO
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
1.5C
2.72
5.78
6.94
leduce
1.50
2.72
5.78
6.99
605
716
890
980
[ core
605
716
890
980
10.6
18.6
.38.4
41
angle
10.6
18.6
38.4
41
2.745
1.344
.518
.337
2.745
1.344
.518
.337
.012
.014
.017
.018
.012
.014
.017
.018
-
.052
.016
.0059
.0052
.038
.0145
.0059
.0052
18.0
1.4
0.1
0.1
2.45
",57
0.1
0.1
155.0
62.0
25.0
22.0
155.0
60.28
25.0
22.0
.90
1.8
4.3
5.6
•
.90
1.8
4.3
5.6
I
VO
-------
ENGINE: JT15D
V comb: >55 ft3,
S comb: 6.16 ft'
PRODUCTION
T rated: 2500 Ibs
ir : 10.2
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
Gitm)
1.82
4.51
9.31
10.12
Mod. I
1.78
4.52
Q sn
LO.OO
tod. F
1.78
4.59
9.52
LO.OO
T3
(°R>
659.13
905.9
1118.1
1147.3
.ame 1
663.4
992.2
1140
1147
Lame T
661.6
926.4
L143.3
L147
M
(#/S)
5.4?
11. 1C
20. 5£
22.2'
ube
5.01
10.74
19. 5C
22.00
ibe
4.87
•
10.67
19.49
22.00
a
1.0412
.2543
.0849
.074(
.9541
.2365
.0745
.0740
tod. N
.9304
.2269
.0745
.0740
f/a
.0099
.0125
.0174
.0182
.0104
.0132
.0179
.0183
>zzle
.0099
.0125
.0179
.0183
•
•
.
l-nc
.055
.0066
.0003
.0002
.0076
.0015
.0003
.0003
.0229
.0025
.0003
.0003
HC
36.97
2.24
0
0
.84
.03
0
0
9.56
.2
0
0
El
CO
90.94
L9.5
1.19
1.01
>9.43
6.41
.8
.6
60.70
9.78
1.12
, -6
N0x
2.32
5.10
9.10
10.10
2.83
5.75
10.2
10.3
1.95
5.51
10.05
10
I
VO
Ul
-------
ENGINE: TFE 731
V comb: .706 ft;?
S comb: 7.00 ft
PRODUCTION
T rated:
•a :
c
3230 Ibs
12.68
IDLE POWER:
6.61% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P*
3
fc»tm)
.84
4.60
1 .08
2.15
ir as
axi i
L.84
T3
<°R)
02.5
50.3
241.9
283.7
1st a
le
50.3
M
(///S)
5.33
2.15
5.92
7.73
4.57
•
ft
.686
.190
.048
.041
.372
f/a
0097
0118
0147
0155
0110
\
•
.
]
L-nc
.035
.006
.0003
.0003
,0047
]
HC
23.03
2.56
.012
.077
.73
El
CO
62.67
16.27
1.26
1.02
17.46
N0x
2.88
6.37
15.80
18.13
1
3.86
-------
ENGINE: ALJ 502D
V comb:
S comb:
PRODUCTION (F102)
T rated: 6500 Ibs
6.1
IDLE POWER:
6.1% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
Airblast
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P-
3
tetm)
6.1
(ALF;
T3
(°R>
730
890
1110
1120
02)
730
890
mo
1120
M
(///S)
16.5
21.8
22.5
.
a
f/a
.0145
.0234
.0246
.021
•
L-nc
.045
.001
.020
j
HC
17.5
6.2
•
ui.
CO
118
57
•
NO
X
2.5
5.0
13.0
13.2
4.0
6.8
13.0
13.2
-------
ENGINE:
V comb:
S comb:
PRODUCTION
M45H
T rated: 7500 ibs IDLE POWER:
IT :
c
16
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
PT
J
(atm)
T3
(°R>
M
(///S)
.
ft
3.4
1.0
n.3.2
0.20
3.4
1.0
0.22
0.20
f/a
•
•
L-nc
.090
.019
,nn?9
.0026
.014
.0026
.0003
.0003'
HC
81.6
11.0
1.0
0.9
7.7
0.9
0.1
0.1
•
El
CO
80
40.5
8.5
8.0
31.0
8.0
1.4
1.3
•
N0x
1
•
vO
00
-------
ENGINE:
V comb:
S comb:
PRODUCTION
RB401
T rated:
n :
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
PT
J
Utm)
T3
<°R)
M
(///S)
,
•
ft
I
f/a
•
L-nc
HC
•
El
CO
NO
X
-------
ENGINE: CF6-50C
V comb: 1>94 f3
S comb: 16.79 ft2
PRODUCTION
T rated:
IT :
c
51000 Ibs
29.8
IDLE POWER:
3.4 % rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
tetm)
2.91
11.70
25.85
29.80
)A Con
2.93
3.45
4.74
9.53
T3
(°R>
773
1134
1415
1477
Eiguar
778
L1134
1415
1469
M
a
(///S)
31.99
L04.9
503.3
127.3
:lon
10.87
30.65
37.70
73.43
•
n
.576
.079
.0219
.0169
,,•14.4
.208
.0859
.0431
f/a
.011
.014
.0214
.0231
.0111
.0140
.0212
.0230
>
•
l-nc
.043
.001
.00008
.00006
.006
.006
.001
0
HC
30.0
.010
.010
.010
2.0
.1
0
0
El
CO
73.0
4.30
.30
.20
19.0
23.4
5.5
2.2
NO
X
2.50
10.00
29.50
35.50
1.6
6.3
5.3
9.6
.
o
o
-------
ENGINE: CF6-6D
V comb: 2.63 ft3 T rated: 3890o ibs
S comb: TT : 24.7
PRODUCTION
IDLE POWER:
3.34% rated
M
El
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
Double
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
3
2.73
4.52
Annula
J
783
1403
a
22.3
,
156.6
•
ft
.326
.0140
f/a
.0132
.0244
•
.
L-nc
.032
.0029
00066
00066
HC
20.5
1.80
.60
.60
CO
61.2
6.00
.60
.60
•
NO
X
4.59
10.75
27.29
34.00
1
•
-------
ENGINE:
V comb:
5 comb:
PRODUCTION
CFM56
.774 ft
rated: 22,000 Ibs IDLE POWER:
: 24
4 % rated
P, T, M
3 3 a
MODE (atm) (°R) (///S) ft f/a l-nc
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
2.82
9.97
21.23
24.14
tod if i
763.9
1094.4
1360.6
1417.1
ed com
13.47
42.41
7-8. 90
87.64
>. wit
•
.6529
.1150
.0336
.0266
i sect
.0147
.0164
.0246
.0265
>r bur
i
•
.
.0249
.0016
.0005
.0005
.0042
El
HC CO N0x
9.14
.29
0
0
.25
•
72.85
5.71
2.29
2.29
17.3
2.14
7.3
16.1
18.2
•
•
o
NJ
-------
ENGINE:
V comb:
S comb: 29.73 ft
PRODUCTION
JT3D-7
4.86 ft3, T rated: 19QOO Ibs
V 13'5
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
p
3
Catm)
2.04
5.5E
11.84
13.63
T,
3
650
911
1133
185.8
M
a
(///S)
33. 8S
91.1:
68.48
86.86
.
ft
.5799
.1572
.0497
.0389
f/a
.0083
.0094
.0135
.0148
-
]
L-nc
.0818
.0034
.0003
.0002
l
HC
69.1
0.5
0.1
0.1
Jl
CO
91.9
12.8
1.1
0.5
•
N0x
3.3
8.0
14.4
19.1
*
•
.
o
OJ
-------
ENGINE: JT8D-17
V comb: 2.70 ft3
S comb: 11-65 Et*
PRODUCTION
P T
P3 A3
MODE (3tm) (°R)
T rated:
V 16-9
•
M
a
(///s) n
16,000 Ibs. IDLE POWER:
f/a
6 % rated
EI
l-nc
HC
CO
NO
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
2.86
6.83
15.07
17.39
Verati
rfith r
2.86
6.83
15.07
17 3°
742
964
1220
1286
ng noz
icher
742
964
1220
1286
31.94
69.37
33.19
50.30
le
rimar
31.94
69.37
.33.19
.50.30
.4518
.1354
.0390
.0301
r zone
.4518
.1354
.0390
.0301
.010
.0112
.0164
.0182
.010
.0112
.0164
.0182
.019
.003
.0003
.0002
.0032
.0008
.0001
.0001
11.4
.80
.10
.10
.09
.122
.002
.01
40.9
10.4
.84
.67
13.4
3.16
.591
.54
4.0
8.2
18.6
22.7
4.24
7.32
17
19.95
I
M
o
-------
ENGINE:
V comb:
S comb:
PRODUCTION
JT9D-7
T rated: 45, 590 Ibs. IDLE POWER:
»„' 21.7
% rated
P3 T3 Ma
MODE (Atm) (°R) (///S) ft f/a 1-c
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIHBOUT
TAKEOFF
3.74
8.98
19.18
21.7
VORBl
3.74
6.80
6.80
6.80
Aerat
820
1064
1330
1384
820
1064
1330
1384
ng no
37.04
97.22
186.1
2O6.5
37.04
97.22
186."
206.5
zle
•
.1710
.0592
.0177
.0142
V com
.2577
.1466
.1716
.1722
.0105
.0140
.0206
.0226
=2.93
.0105
.0140
.0206
.0226
'
•
•
-
•
038
.0033
.0003
.0004
.0112
.0049
.0095
.0084
.0024
El
HC CO
25
1.2
.16
.21
3
.9
2.9
3.0
.87
• •
70
10
.80
1.0
37
17.6
30
25
6.9
•
N0x
3.2
10.1
22.3
30
•
3.7
7.1
12.1
15.7
•
•
o
01
i
-------
ENGINE:
V comb:
5 comb:
PRODUCTION
JT10D
T rated:
rr :
IDLE POWER:
% rated
P3 T3 Ma
MODE (atra) (°R) (///S) ft f/a l-nc
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLLMBOUT
TAKEOFF
.
•
\
•
•
•
•
El
HC CO
t
i
NO
X
•
•
o
CTi
-------
ENGINE:
V comb:
S comb:
PRODUCTION
Spey Mk511
T rated: 11,400 Ibs.
*„'• 19.1
IDLE POWER:
% rated
MODE
IDLE
APPROACH
CUMBOUT
TAKEOFF
ADVANCED :
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
P3
Utm)
T3
(°R>
M
(#/S)
•
ft
f/a
>
-
L-nc
.126
.006A
.0006
.0004
HC
116
2.1
5 0
> 0
El
CO
105.6
19.7
2.7
2
NO
X
•
-------
ENGINE:
V comb:
S comb:
PRODUCTION
RB211-22B
T rated: 42,000
V 25
IDLE POWER:
2 % rated
MODE
M
(aitm) (°R) (///S) ft f/a
El
l-nc
HC
CO
NO
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
ADVANCED:
IDLE
APPROACH
CLIMBOUT
TAKEOFF
•
0.33
).043
0.33
0.043
-
•
.090
.010
.0012
.0001
.010
.0013
81.6
5.2
0.3
1
5.2
0.3
80
23.5
3.3
23.5
3.7
•
o
oo
-------
Appendix B
Analysis of the Format of the Standards
The present aircraft standards can be represented by two multipli-
cative terms, one representative of the combustor performance (in terms
of mass of pollutant per mass of fuel), and the other representative of
the fuel consumption efficiency of the engine (in terms of mass of fuel
per level of useful output), both terms being weighted over the prescribed
landing -takeoff cycle:
standard = (combustor performance ) x (fuel consumption)
or
standard = mass of pollutant x mass of fuel = El x SFC
mass of fuel useful output
or simply
standard = mass of pollutant
useful output
Compliance with the standard can thus be approached in two ways,
(1) by improvement of the combustor performance (ie. reducing the emissions
index) and (2) by improvement of the fuel consumption efficiency (ie.
reducing the SFC). The latter approach is accomplished principally by
modification of the thermodynamic cycle of the engine, that is, modification
of the compressor pressure ratio and the fan bypass ratio. This standard
thus encourages fuel economy through the judicious choice of the thermo-
dynamic cycle of the engine.
However, for engines already in existence, the thermodynamic cycle
and hence the SFC is fixed. Therefore compliance with the standards has
to be accomplished by improving the combustor emission performance. For
engines with low SFC, compliance with the standards will be less difficult
than for engines with high SFC. Engines with very high SFC will not be
able to meet the standards without the use of exotic technology (eg.,
catalysts) which is still in the exploratory stage.
-109-
-------
Appendix C
Effects of the Use
of Tap Water
------- |