FINAL TECHNICAL REPORT
COLLECTION AND ASSESSMENT
OF AIRCRAFT EMISSIONS BASE-LINE DATA
TURBOPROP ENGINES
(Allison T56-A-15)
J. M. Vaught S. E. J. Johnsen
W. M. Parks R. L. Johnson
Detroit Diesel Allison Division • General Motors
Indianapolis, Indiana
EDR 7200
September 1971
Environmental Protection Agency
Office of Air Programs
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FINAL TECHNICAL REPORT
COLLECTION AND ASSESSMENT
OF AIRCRAFT EMISSIONS BASE-LINE DATA
TURBOPROP ENGINES
(Allison T56-A-15)
J. M. Vaught
W. M. Parks
S. E. J. Johnsen
R. l. Johnson
Detroit Diesel Allison Division. General Motors
Indianapolis, Indiana
EDR 7200
Septe m ber 1971
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Allison
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FOREWORD
This report describes the work performed by Detroit Diesel Allison, Division of General
Motors, Indianapolis, Indiana, for the Environmental Protection Agency (EPA), Office of Air
Programs, Ann Arbor, lVIichigan, under EPA Contract No. 68-04-0029 during the period
1 June through 16 August 1971. Mr. C. L. Gray was the Project Officer for EPA and Mr.
E. S. McLean was the Contracting Officer for EPA.
Detroit Diesel Allison has assigned Report Number EDR 7200 to this publication which was
submitted in August 1971.
Publication of this report does not constitute Environmental Protection Agency approval of the
report's findings or conclusions.
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Allison
Section
I
II
III
IV
T ABLE OF CONTENTS
Title
Introducti. .n
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Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Experimental. . . . . . . . . . . . . . . . . . . . . .
Engine Description. . . . . . . . . . . . . . . . .
General Operation. . . . . . . . . . . . . . . . . . . . . . . . .
Specific Performance. . . . . . . . . . . . . . . . . . . . . . .
Applications. . . . . . . . . . . . . . . . . . . . . .
Production Engine Testing. . . . . . . . . . . . . . . . . . .
Emission Measurement . . . . . . . . . . . . . . . . .
Measurement System. . . . . . . . . .
Measurements Taken. . . . . . . . .
Sampling. . . . . .
Instrument Calibration
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Automatic Data Recording
Test Procedure. . . . . .
General. . .
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Exhaust Recirculation at Reverse
Low Speed Ground Idle.
Measurement Procedure. .
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Test Data. . . . . . . . . . . . . . . . . . . . . . .
Data Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Drainage . . . . . . . . . . . . . . . . . . . . . . .
Fuel Analysis. . . . . . . . . . . . . . . . . . . .
Particulate Emissions. . . . . . . . . . . . . . . . . . . . . . . .
Starts and Accelerations. .
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Commentary. . . . . . . . . . . . . . . . . . . . . . . . . .
Testing of Production Engines. . . . . . . . . . . . . . . . . .
Sampling and Sample Handling. . . . . . . . . . . . . . . . . .
Carbon Monoxide and Carbon Dioxide - . . . . . . . . . . . . . .
Oxides of Nitrogen. . . . . . . . . . . . . . .
Hydrocarbons. . . . . . . . . . . . . . . . . . . . . . . . . . .
Aldehydes. . . . . . . . . . . . . . . . . . . . . . . . .
Smoke. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Particulates. .
Transients
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Analysis. . . . . . . . . . . . . . . . . . . . . . . . . .
General Approach. . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Test Cycles. . . . . . . . . . . . . . . . . . . . . . . . . .
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.Allison
Section
V
VI
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
TABLE OF CONTENTS (Cont)
Title
PTS Cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
L TO Cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Analysis. . . . . . . . . . . . . . . . . . . . . . . . .
General Preparation. . . . . . . . . . . . . . . . . . . . . . .
Regression Analysis. . . . . . . . . . . . . . . . . . . . . . .
Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regression Analysis. . . . . . . . . . . . . . . . . . . . . . .
L TO Computation. . . . . . . . . . . . . . . . . . . . . . . . .
Sampling Quality. . . . . . . . . . . . . . . . . . . . . . . . .
Smoke Index Correlations. . . . . . . . . . . . . . . . . . . . .
Aldehyde Measurements. . . . . . . . . . . . . . . . . . . . .
Particulates. . . . . . . . . . . . . . . . . . . . . . . . . . .
Commentary. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V.ariability of Results. . . . . . . . . . . . . . . . . . . . . . .
L TO Cycle. " . . . . . . . . . . . . . . . . . . . . . . . . . . .
Importance of Transients. . . . . . . . . . . . . . . . . . . . .
Conclusions and Recommendations. . . . . . . . . . . . . . . . . . . .
References. . . . . . " . . . . . . . . . . . . . . . . . . . . . . . . . .
Description of Measurement Methods. . . . . . . . . . . . . . . . . .
Emissions Data Tables. . . . . . . . . . . . . . . . . . . . . . . . . .
Computation Methods from ARP1256 . . . . . . . . . . . . . . .
Airflow at Various Values of Compressor Inlet Pressure
and Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables of Analytical Results. . . . . . . . . . . . . . . . . . . . . . .
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Figure
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4-1
4-2
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4-4
LIST OF ILLUSTRATION
Title
T56-A-15 engine cutaway. . . . . . . . . . . . . . . . . . . . . . . .
T56-A-15 engine airflow and combustion schematic. . . . . . . . . . .
Schematic of system used for emission measurements
ofproductionT56-A-15 engines ................
Installation of test instrumentation. . . . . . . . . . . . . . . . . . .
Hydrocarbon analyzer and calibrating gas cart. . . . . . . . . . . . .
LIRA cart with CO, C02, and NO analyzer. . . . . . . . . . . . . . .
Hydrocarbon analyzer remote burner-oven. . . . . . . . . . . . . . .
Smokemeter and grab sample panel. . . . . . . . . . . . . . . . . . .
On-line strip chart recorders. . . . . . . . . . . . . . . . . . . . . .
Probe and sampling line installed on T56 -A-15 engine. . . . . . . . .
Rear view of probe and sampling line installed on
T56-A-15 engine. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heated sample line construction. . . . . . . . . . . . . . . . .
Hot start emissions. . . . . . . . . . . . . . . . . . . . . . . . . . .
Cold start emissions
. . . . . . . .
. . . . .
. . . .
. . . . . . . . . .
Hot start emissions. . . .
T56 -A-15 emission transient data
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T56-A-15 emission transient data
T56-A-15 emission transient data
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T56 -A-15 emission transient data. . .
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T56-A-15 emission transient data. . . . . . . . . . . . . . . .
T56-A-15 emission transient data. . . . . . . . . . . . . . . . . . . .
T56-A-15 production test specification run schedule. . . . . . . . . .
Schematic diagram of data handling process. . . . . . . . . . . . . . .
Smoke index vs power. . . . . . . . . . . . . . . . . . . . . . .
Average LTO emissions. . . . . . . . . . . . . . . . . . . . .
v
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. Ta ble
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3 - III
3-1V
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4- VII
4- VIII
4-1X
LIST OF TABLES
Title
Allison T56-A-15 performance ratings. . . . . . . . . . . . . . . . . .
Allison commercial turboprop engines. . . . . . . . . . . . . . . . . .
Allison turboprop engines in service. . . . . . . . . . . . . . . . . . .
Particulate emissions, T56 engines. . . . . . . . . . . . . . . . . . .
Representative landing-takeoff cycle for Model 501
turboprop aircraft. . . . . . . . . . . . . . . . . . . . . . . . . . .
Dictionary of raw input data. . . . . . . . . . . . . . . . . . . . . . .
Emission performance summary. . . . . . . . . . . . . . . . . . . . .
Summary table of pounds of pollutant over the LTO
mission for individual T56 engines. . . . . . . . . . . . . . . . . .
Summary of pounds of pollutants per thousand pounds of fuel over
the LTO mission for individual T56 engines. . . . . . . . . . . . . .
Rate of formation of pollutants averaged over all engines for each
mode of the L TO cycle. . . . . . . . . . . . . . . . . . . . . . . . .
Carbon balance results from Engine 108516 in LTO cycle. . . . . . .
Particulate emission rates. . . . . . . . . . . . . . . . . . . . . . . .
Mass emissions during transients. . . . . . . . . . . . .
. . . . . . .
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.Allison
w.!1
I. INTRODUCTION
Public Law 91-604. "Clean Air Amendments of 1970." requires establishment of exhaust
emission standards for ?.ircraft by the end of 1971. Detroit Diesel Allison. under contract to
the Environmental Protection Agency. accomplished a program with the objective of collecting
and assessing base-line exhaust emission data on Allison T56-A-15 turboprop engines.
During the contract period of performance, computerized data handling and statistical analysis
programs were developed. exhaust emissions of eleven production T56-A-15 engines were
measured, and a landing-takeoff (LTO) emission test cycle was developed.
This report. which covers the contract effort and describes in detail such items as measure-
ment systems. test program. data analysis, and computation methods, contains five major
sections with primary emphasis on three: Experimental, Analysis, and Conclusions and
Recommendations. It is presented to promote .industry-wide information exchange and aid in
establishment of aircraft emissions standards and measurement techniques.
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- AJilison
:"'\"'.."".-,~ .1
n.
SUMMARY
Exhaust emissions data were collected and evaluated from eleven new T56-A-15 military turbo-
prop engines during their production-line performance evaluation. The normal production test
schedule was used. The following measurements were made:
. CO. C02, and NO-Luft-type Infrared Analyzers (LIRA)
. Hydrocarbons- Heated Flame Ionization Detector (Fill)
. Smoke- SAE smokemeter
. NO and N02-Chemiluminescent analyzer
. NO plus N02-Modified Saltzman method
. Oxygenated compounds- MBTH method
Fuel drainage was also measured.
furnished from other experiments.
Particulate data according to the LACAPCD method were
Experimental data were analyzed by converting the concentration values measured for each
engine to mass emissions over a landing and takeoff (LTO) cycle representative of a com-
mercial flight with T 56-type engines and then performing a statistical analysis to obtain mean
and standard deviation values.
Emission measurements were satisfactory; the average emission levels and variations were
determined over the operating range of each engine. However, the variations could not be
specifically proportioned between true engine variation, instrument variability, and that in-
curred by measuring a production test cycle and converting to the emissions cycle. It is
recommended that true engine variability and instrument variability be assessed by a test
which includes a large number of engines (samples) and a statistically planned evaluation of
instrument error.
The LTO emission test cycle used for the analysis was developed from a study of Model T56
engine-powered aircraft. It showed that LTO total mass emissions were highly sensitive to
the length of time that the aircraft was held stationary during ground operations. Because of
the degree of its influence on total mass emissions, aircraft handling and all of its variabilities
should be divorced from engine emissions test cycles.
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III.
EXPERIMENTAL
This section describes the testing, the methods and equipment used, and the data directly ob-
tained. Comments on the experimental work are also included.
ENGINE DESCRIPTION
The engine selected for exhaust emissions evaluation was the Allison T56-A-15 turboprop en-
gine. This model is on,~ in a series of military T56 engines; the Allison Model 501 is their
commercial counterpart. All engines in these series consist of an internal combustion gas
turbine power section, connected by extension shafting and a supporting structure to a single
reduction gear assembly which has a single propeller shaft. In the T56-A-15, this shaft is
offset above the power section center line. The power section contains six combustion cham-
bers of the through-flow type assembled within a single annular chamber and incorporates a
fourteen- stage axial-flow compressor directly coupled to a four- stage air-cooled turbine
(Figure 3-1).
7200-1
Figure 3-1. T56-A-15 engine cutaway.
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Allison
.--.,
General Operation
....,
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During operation, air enters the power section through the air inlet housing (Figure 3- 2) and
is compressed by the compressor. The compressed air flows through the diffuser into the
combustion liners where fuel is introduced and the fuel-air mixture is ignited, after which it
burns continuously. The re,mltant gases exit through the aft ends of the combustion liners and
flow through the turbine where the energy of the gas is extracted and converted into usable
kinetic energy to drive the compressor and reduction gear. The gases exiting the turbine have
some residual energy whi;::h creates a small amount of jet thrust. The power supplied to the
reduction gear by the power turbine is converted from high rpm-low torque energy to the
lower speeds and subsequent higher torque required for efficient propeller operation.
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Engine operation is controlled by coordinated operation of the fuel, electrical, and propeller
control systems. A characteristic of this turboprop engine is that changes in power are not
related to engine speed but, rather, to turbine inlet temperature. During flight, the propeller
maintains a constant engine speed, which is 100% rated speed of the engine and is the design
speed at which most power and best overall efficiency can be obtained. Therefore, fuel flow
is changed to affect power requirements. An increase in fuel flow results in a higher turbine
inlet temperature and a corresponding increase in available energy at the turbine. The tur-
bine then absorbs more energy and transmits it to the propeller in the form of torque. The
propeller, in order to absorb the increased torque, increases blade angle and, in the process,
maintains constant engine rotational speed.
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Figure 3-2.
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Allison
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Specific Performance
Two specific performance ratings as a function of power setting for the Allison T56-A-15
turboprop engine are summarized in Table 3-1. All performance ratings are given for stan-
dard sea level static con litionso
Table 3- I.
Allison T56-A-15 performance ratings.
(Standard sea level static conditions)
Power
setting
Engine rotor
speed (rpm)
Min
eshp*
Compr press.
ratio (Rc)
Airflow
(lb / see)
Fuel flow
(lb/hr)
Turb inlet
temp (OF)
Jet thrust
(lb)
Normal
Takeoff
13,820
13, 820
4365
4910
10
10
33
33
2260
2460
1850
1970
760
797
':'Equivalent shaft horsepower
Applications
The T56-A-15 engine-a Series III version in the line of T56 models-is in quantity production
as the powerplant of the Lockheed four-engine C-130 Hercules. Other T56 engines power the
Lockheed P-3 Orion (a four-engine Navy ASW aircraft), the Grumman C-2 and E-2 (two-engine
carrier-based Navy planes), and variations of the C-130 transport.
Two models of the Allison 501 turboprop engine are operational in commercial aircraft. The
Model 501-D13 series, although no longer in production, powers the four-engine Lockheed
L-188 Electra and the two-engine Convair 5800 The Model 501-D22 series is used in the
Lockheed four-engine commercial Hercules-the L-382 and L-1000 The 501-D22A, which is
the commercial counterpart of the Allison T56-A-15, is now in .limited production.
Table 3-II is a listing of the Model 501 engine applications. The quantities of engines produced
for commercial and military use are summarized in Table 3-III.
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.Allison
Table 3- n.
Allison commercial turboprop engines.
Power rating
Engine model* (eshp**) Aircraft Status . Remarks
501-D22A 4680 Lockheed Model 382D, Limited production
E, and F transport (3 engines on order>
501-D22C 4680 Aero Spacelines Mini Service only 14 engines
Guppy and Super Guppy delivered
outsized transports
501-D22 4050 Lockheed Model 382B Service only Engines are
transport being con-
verted to
Model 501-
D22A
501-D13 3750 Lockheed Model 188 Service only
transport
501-D13A 3750 Lockheed Model 188 Service only Hamilton
transport Standard
propeller
501-D13D 3750 Allison Convair Service only
Model 580
501-D13H 3750 Allison Convair Service only
Model 580
Water-alcohol
augmentation
for high alti-
tude airfield
performance
*Models 501-D22A & C basically the same as Military T56 Series nI engines.
Model 501-D22 basically the same as Military T56 Series n engines.
Model 501-D13A, D, & H basically the same as Military T56 Series I engines.
**Equivalent shaft horsepower.
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Allison
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Table 3-III.
Allison turboprop engines in service.
Engine model Type Quantity manufactured
501-D13 (Series 1) Commercial 1809
T56 Series I Military 1454
501-D22 (Series II) Commercial 50
T56 Series II Military 4374
501-D22A (Series III) Commercial 170
T56 Series III Military 1860
Total Commercial 2029
Military 7688
PRODUCTION ENGINE TESTING
Emission measurements were taken during routine acceptance testing of Model T56-A-15
turboprop engines. The first six engines measured were run after a final run schedule; mea-
surements of the remaining five followed an initial run. The schedules are nearly identical.
Both include a power calibration run covering the entire range of engine performance. The
complete test procedure is defined in Detroit Diesel Allison Production Test Specification
(PTS) No. 702. Acceptance Test of Production Turboprop Engines. Data recorded during the
runs included:
. Engine identification
. Date and time of day
. Test stand and operator
. Fuel flow (lb Ihr)
. Torque (in. -lb)
. Shaft speed (rpm)
@ Shaft horsepower (HP) ':'
e> Compressor inlet pressure (in. Hg abs)
II Compressor inlet temperature (OF)
G) Airflow (lb/sec)':'
. Wet bulb tern,perature (OF)
. Dry bulb temperature (OF)
*Calculated from test measurements.
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Allison
EMISSION MEASUREMENT
Measurement System
The measurement system used for these tests was designed to operate as an integrated sys-
tem, using the SAE Preliminary Aeronautical Recommended Practice1':' as a guide. The sys-
tem was installed in production test cell No. 117 at Detroit Diesel Allison Plant No.5 on 15
June 1971. It was used to measure the emissions- including transient and starting emissions-
for this program. A schematic of the system is shown in Figure 3-3.
Note: Calibration provisions not shown
~
1/4-ln. stainless
steel heated line
Unheated line
=
(Not used on first four engines)
Hydrocarbon
analyzer (FID)
(Unburned HCx)
I - ----,
I NO I
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I LIRA NDIR I
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I CO I
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I C02 I
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TECO
(NO and N02)
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I Detroit Diesel I
I Allison I
I Bacharach I
smoke sampler
(Modified)
Wet gas
meter
MBTH
aldehyde bubbler
(when used)
I
Grab sampler I
I (CO, C02) I
I I
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I Saltzman I
I sampler I
I (NO+ N02) I
L- --------,
4 psi bypass
7200-3
Figure 3-3. Schematic of system used for emission measurements of
production T56-A-15 engines.
':'Superscript numbers correspond to the references listed in Section VI of this report.
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Measurements Taken
During production testing, the following measurements were taken over the full range of en-
gine power levels. All measurement methods are described in detail in Appendix A.
. Total Hydrocarbons-Allison Heated Flame Ionization Detector (F1D)
. Carbon Monoxide. Carbon Dioxide, and Nitric Oxide-Mine Safety Appliances. Luft-type
Infrared Analyzers (LIRA)
. Nitric Oxide (NO) plus Nitrogen Dioxides (N02)- Modified Saltzman wet chemical analysis
. NO and N02- Thermo Electron Co. chemiluminescent analyzer
. Smoke-Bacharach smokemeter. modified to comply with ARPl179 2
. Aldehydes-MBTH method wet chemical analysis
Figure 3-4 is a photograph of these instruments installed in the test stand corridor. The
analyzer console of the FID and the calibrating gas cart are shown in Figure 3 - 5, the LIRA
cart in Figure 3-6, the Fill remote burner and oven in Figure 3-7, the smoke and grab sample
panel in Figure 3- 8,. and the on-line L& N recorders in Figure 3- 9.
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Figure 3-4. Installation of test instrumentation.
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Allison
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Figure 3-5. Hydrocarbon
analyzer and calibrating
gas cart.
.
Figure 3-6. LIRA cart with
CO, C02' and NO analyzer.
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remote burner-oven.
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Figure 3-8. Smoke meter and
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J
Figure 3-9. On-line strip chart recorders.
n
J
Sampling
o
Probe
~l
~
A representative sample was obtained with a 28-hole sampling probe supplied by Detroit Diesel
Allison. The probe was designed to minimize sampling error; it aCCOlll1ts for radial discrep-
ancies by sampling at the area center of four equal annular areas in the tailpipe. Circumfer-
ential discrepancies were avoided by using seven probe legs to sample a six-combustor engine.
The probe clamped directly to the T 56 tailpipe flange but had negligible effect on engine per-
formance. Validity of the sample was proved by carbon balance (carbon into the engine as fuel
is equated to measured carbon out) which showed preliminary agreement of 5%. Results of a
more detailed analysis (refer to Section IV of this report) showed even closer agreement.
Figures 3-10 and 3-11 show how the probe was attached to the engines for testing.
l
~I
J
l
J
3-10
-------
Ie
[
10
Ie
[
c
Figure 3-10. Probe and sa ~pling
line installed on T56-A-l~ ,mgine.
o
[
[
I[
I~
C
Allison
.~
-" -: - ~ ; III..
.., ....
,~ - ~.,.~
. ( ~~..
, "
IQ
IC
iG
o
o
C
ID
Figure 3-11. Rear view of probe and
sampling line installed on T56-A-15
engine.
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Allison
Lines
Heated sample lines were used throughout the tests between the engine and the FID and the en-
gine and the slnokemcter. Lines were made of O. 250-in. stainless tubing; they were wrapped
with Teflon tapf', 480-watt ;-'lectrical heating tapes, woven asbestos sleeving, and again with
Teflon tape. The tube Sf' ".I.ons were joined with instrumented unions or tees for monitoring
line and gas temperatures. The detailed construction is shown in Figure 3-12.
Approximately 25 n of j,..ated line were required to reach the Fill, and eight additional feet
('onve~-ed the sample to the smokemeter-Saltzman-grab sample rig. Unheated O.250-in.
stainless steel tubing was run to the LIRA cart. Flexible O. 187-in. nylon line connected the
alrlehyde and TECO rigs when used. The sample line was run either horizontally or down-
ward; no upward bends were required. Two Variacs in the FID cabinet and one external unit
furnished power to the four line heaters which were maintained at 300 :f:10°F.
The heated line is the one running horizontally just above the FID cabinet in Figure 3-7 and
can be seen at the engine in Figure 3-10.
Flow Rates and Temperatures
On the first four C'ngines tC'stcd, sample flow was marginal at all except high power test points.
Subsequent to the fourth ~'ngine, a 1.0- sefm stainless steel syphon bellows pump was installed
between the probe and the FID inlet (Figure 3-3). The pump body was heated and insulated
similar to the sample line. This pl1mp pcrmittC'd simultaneous operation of all instruments
Teflon tape
Gas temp
thermocouple
Asbestos sleeving
Heating tape
stainless steel tube
7200-12
Figure 3 -12.
Heated sample line construction.
-------
-"'-
-- "-~-'". .Allison
-
'0;.&1"'" "",",-\;~.
except the FID, which required careful pressure and flow adjustments, and provided suffiCient
sample flow at all power settings.
Valves
Shutoff valves in the sample lines were Hoke Roto-Ball units with their 0.375-in. NPT openings
reduced to 0.250-in. Swagelok fittings. Valves on the Saltzman rig were 0.250-in. Hoke
Swagelok needle valves with toggle operators. Internal shutoff in the FID was an electrically
operated Hoke Roto-Ball unit, and flow regulation was provided by a motor-operated needle
valve. Adjustable relief valves furnished overpressure protection in the FID, LIRA, smoke.
and Saltzman rigs. Nominal settings were 4 to 5 psig.
Purge System
Purge capabilities using bottled nitrogen were provided to prevent fouling of the sample lines
during starts and when no data were desired. A 200-ft3 cylinder of nitrogen and the necessary
valving were used to introduce the purge gas at the LIRA cart initially and at the bellows pump
inlet after its installation.
Instrument Calibration
Shown at the right in Figure 3- 5 is the portable cart containing the calibration gas bottles. The
fuel, air, and hydrogen for the Fill were also supplied from this cart. Sufficient regulators
.
were available to minimize the time required to switch gases.
Flexible tubing was run from a central bottle cart for calibration of all instruments.
lowing gases were available for calibration purposes:
The fol-
C02-I. 02% and 5.78%
CO- 52.2, 310, and 514 ppm
NO-21.5, 55.2. and 154 ppm
C02 + CO-3. 61 % plus 560 ppm
HCx-4. 27 ppm CH4; 10.4. 105,
and 203 ppm C3H8
Automatic Data Recording
The "on-line" outputs of analyzers during calibration and data acquisition were connected to
separate L&N Speedomax strip chart recorders. A chart speed of 2 in./min was standard.
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Allison
TEST PROCEDURE
General
During the emission testing of the eleven engines, normal production test procedures were
used except that the initial idle running was extended slightly to switch off the nitrogen purge
and bring the emission equipment on the line. The emission measurement crew was in con-
tact with the engine operator at all times during the test and was continuously advised of the
engine operating condition. Except for transients, data were taken only after the engine had
stabilized.
Contract requirements of ten engines were met on June 29th. One more engine was available
in the June production schedule and was measured with minimum additional effort.
Exhaust Recirculation at Reverse
The original plans were to use the measured values of emissions during the reverse thrust
mode. However, examination of the results of the initial engine tests showed the existence-
on the test stand-of a high component of exhaust recirculation and inlet heating of +30°F.
This is not characteristic of normal aircraft operations where reverse is not used below 50
knots forward speed. Hence, it was determined that reverse mode emissions could be inter-
polated from the normal running data; and emission measurements in the reverse mode were
dropped after the first four engines.
Low Speed Ground Idle
During the testing of the first four engines, unexpected low values of hydrocarbons and carbon
monoxide were obtained at ground idle. A reevaluation of the ground operation of T56-powered
aircraft revealed that during taxi the throttle position was at a higher rpm setting than when
the aircraft was held on the ramp. The two operational modes are compared in the following
tabulation.
Aircraft Equivalent CO concentration
operation Power setting shaft horsepower Engine rpm (ppm vol)
Taxi Ground idle (GI) 850 (max) 13,500 30-70
Holding Low speed ground 160 (max) 10,000 320-450
idle (LSGI)
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Allison
:;a:.w
Because holding is a significant part of the ground operation of T56-powered aircraft. the
10. OOO-rpm LSGI power setting was included for the last six engines tested. Measurements
of aU effluents were made at that power.
Measurement Procedure
Generally. measurements were made only at steady-state points. During most of these, ade-
quate time was available to read the on-line instruments, make a zero instrument check, and
reread the instruments. Grab samples for smoke. NOx. and aldehydes were taken during the
time the instruments were being zeroed. To obtain transients, the instruments were allowed
to record during power level changes throughout the PTS run schedule.
Engine starts were recorded after all other measurements were completed. The hot engine
starts were made approximately five minutes after shutdown. The ambient start was made
the morning after an overnight soak at test stand ambient temperature.
Fuel drainage was collected from the fuel manifold drain valve after each test and averaged to
obtain the drainage for each engine start. Measurement of fuel from other drain points was
unnecessary because the burner case drains collect fuel only after a false start and the fuel
accessory drains only after high seal wear.
TEST DATA
This subsection presents raw data from the power sections tested and the fuel analysis.
Data Tables
Appendix B contains (1) a definition of the PTS set points and (2) a matrix of raw data consist-
ing of engine operating variables and gas composition obtained at various engine power levels.
The PTS schedule requires certain sequencing and repetition of some set points. Where pos-
sible, redundant data were acquired to ensure high quality sampling. This redundancy is obvi-
ous on observation of the data matrix. Every effort was made to acquire data at all of the de-
sired set points.
Fuel Drainage
Fuel drainage values were measured for each engine tested.
The results were:
-------
Engine
108506
108508
108469
108510
108507
108509
108513
108512
108517
108518
108516
Allison
Fuel drainage (cc)
90
95
95
105
90
90
110
90
90
100
95
The average fuel drainage for the eleven engines tested was 95 cc.
Fuel Analysis
A complete fuel analysis was made on the fuel used during test of Engine 108517. The results
were:
Flash point, of
Sulfur content, %
Analine point, of
Smoke point, mm
API gravity
Heating value, Btu/lb
Initial boiling point, of
5%
10%
20%
30%
40%
50%
60%
70%
80%
90%
95%
End point. of
Residue, %
L:..ss, %
Recovered, %
3-16
- 20 to - 2 5
0.3
124.9
23.7
54.1
18,687
152
203
217
231
248
263
283
310
346
383
434
464
481
1.0
1.0
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Allison
""'''.~Ji-''.I
PARTICULA TE EMISSIONS
Particulate measurements from previous tests of T 56 engines are given in Table 3- IV. The
method of measurement was the one used by the Los Angeles Air Pollution Control District,
described in their Sourc' Testing Manual,S in which the particulates are collected by a water
bath irnpinger train. During the laboratory analysis, the particulates are classified as water
soluble, hydrocarbon soluble, and insoluble. The sum of these fractions is the total of the
particulates measured.
Table 3-IV.
Particulate emissions, T56 engines.
Data are in grains I scf of exhaust and were obtained from previous
tests using JP- 5 fuel.
Power setting
Test 1
T56 Series I
Test 2
T 56 Series III
Test 3
T56 Series III
Low speed ground idle
Ground idle
Takeoff
Climb
Approach
Reverse':'
O. 127 O. 108
0.088
0.065 0.096
O. 092
0.088 0.071
O. 090
0.112
0.076
*Interpolated.
STARTS AND ACCELERATIONS
Emissions were measured with on-line equipment on Engine 108518 during starting. This was
the last item of testing to prevent the possibility of "hydrocarbon hangup" because of fuel in the
sampling system. Three starts were run-two hot and one 'cold. A "hot start" is a start per-
formed within ten minutes after shutdown. A "cold start" means that the engine has cooled to
room temperature prior to a start sequence. The emissions measured during engine starting
are plotted in Figures 3-13, 3-14, and 3-15.
-------
1800
1700
1600
1500
0 = HCx
1400
0= CO
1300 6= NO
1200
1100
e
8: 1000
I
GI
C
0 900
'0;
'"
's 800
~
700
600
500
400
300
200
100
o
o
60
70
80
20
30
40
50
10
Time - seconds
Figure 3-13. Hot start emissions
(Engine 108518).
Allison
90
100
7200-13
3-18
1300
1200
1100
1000
e
Q,
Q,
I 700
'"
c
o
'0; 600
'"
's
~ 500
1400
900
800
400
300
200
100
o = HCx
0= CO
6= NO
o
o
50
60
40
80
20
30
70
90
100
10
Time-seconds
7200- 14
Figure 3-14. Cold start emissions
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Allison
-
1400
1300
1200
1100
1000
900
e 800
0-
0-
I
B 700
a;
.!! 600
e
w
500
400
300
200
100
o
o
0= HCx '
O=CO
~ =NO
10
70
90
80
60
30
40
50
20
Time-seconds
7200-15
Figure 3-15. Hot start emissions (Engine 108518).
Engine acceleration and deceleration emissions were obtained during the runs of three engines.
Values of total hydrocarbons, carbon monoxide, and oxides of nitrogen were obtained with the
on-line equipment and are represented by the following plots:
Figure 3-16-Low speed ground idle to high speed ground idle.
Figure 3-17-Flight idle to takeoff, Engine 108507
Figure 3-18-Takeoff to flight idle, Engine 108512
Figure 3-19- Flight idle to takeoff, Engine 108516
Figure 3-20-Takeoff to flight idle, Engine 108516
Engine 108517
No change in unburned hydrocarbons was observed during transients between flight idle and
takeoff; therefore, they were not plotted.
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Allison
400 I
j-- Low speed ground idle
I
HCx I
300 I
I I
e I
c:o. I I
c:o.
I I
'" I
e 200 I
0 I
"0; I
., I
"s
~ I High speed ground idle -1
I I
100 "I I
I I
I
0 I
0 10 20 30 40 50 60 70 80 90 100
Time-seconds
7200-16
Figure 3-16. T56-A-15 emission transient data (Engine 108517).
2. 100
c:o.
I
.,
5 80
"0;
'"
"s 60
~
160
140
I
I
I
I
'I
I
I
I
I
I
120
I-- Flight idle
I
I
I
I
I
I
Takeoff
NO
40
20
o
o
30
80
90
100 110 120
40 50 60 70
Time-seconds
10
20
7200-17
Figure 3-17. T56-A-15 emission transient data (Engine 108507).
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Allison
_1
120 I
Takeoff
100 Flight idle I
'I
e I
8: 80
I I
CD
c:: 60 I
0
"jjj I
CD
Os 40 NO I
t.:I
20
0
0 10 20 30 40 50 60 70 80 90 100 110 120
Time-seconds
7200-18
Figure 3-18. T56-A-15 emission transient data (Engine 108512).
160
140
120
8
c.
c.
I 100
:!!
~ 80
CD
8
t.:I 60
40
20
o
o
NO
Flight idle -1
I
I
I
I
10
20
30
50
40
Time-seconds
7200-19
Figure 3-19. T56-A-15 emission transient data (Engine 108516).
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Allison
160 I
I-- Flight idle
I I
I I
I I
e I
Q. I
Q.
I ! Takeoff --+f
III
I:
0 I I
0iij
III I
Os 60 I
~ I
40
o
o
10
20 30
Time-seconds
40
50
7200-20
Figure 3-20.
T56-A-15 emission transient data (Engine 108516).
COMMENTARY
Testing of Production Engines
No major difficulties were encountered in obtaining emissions from production engines. Con-
siderable care was required to prevent interference with schedule requirements and with the
quality of performance measurements.
During the short period of testing, the crew was able to keep up with a rate of two engines per
day on one instrumented test stand; only one engine was passed because of emissions measure-
ment equipment malfunction. However, the test schedule for each engine had to be extended
because longer initial engine idle periods were needed. The experimental instrumentation and
sample handling system was poorly suited to the environment of production testing which re-
quires rapid, simple, automated procedures. These deficiencies were overcome by maximum
crew effort and the use of additional manpower. One engineer and two technicians were re-
quired to take the emissions measurements. Thus, it is apparent that any aircraft turbine
emission measurement system requires extensive development before it would become accept-
able as a routine production testing process.
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Allison
f'JI>..1
Variability of engine performance because of changes in inlet temperature to the engine and
between engines can be observed in the variation in fuel flow required to reach 1970°F turbine
inlet temperature-the takeoff power point:
Fuel flow Compressor inlet
Engine (lb Ihr) temperature (OF)
108513 2074 102
108517 2150 99
108508 2190 88
108507 2170 94
108506 2152 93
108509 2128 94
108516 2190 81
108518 2260 91
108512 2110 102
108510 2210 85
108469 2090 94
The mass of fuel burned is related to engine performance and inlet conditions. For future
standards, it would seem reasonable to correct mass emissions values to standard inlet con-
ditions.
The production test stand is not the ideal environment for emissions tests. The exhaust re-
circulation encountered at reverse thrust has been mentioned. In addition, fuel and oil spill-
age, oil accumulations, and hydrocarbon solvent engine washdowns for leak checks contribute
to make the hydrocarbon background levels several times higher than the minimum values
emitted by the engine.
Sampling and Sample Handling
The sample probe performed well throughout the testing. ~o maintenance or adjustment was
necessary and no malfunction occurred. Two connections were required for installation of the
probe-one at the clamp nut, which was lockwired, and one at the gas fitting. The total in-
stallation time was less than one. minute. The probe was always indexed with the sample exit
line straight down as shown in Figure 3-11.
A prime number of sampling legs (7) and a large number of sampling holes (28) were chosen
to compensate for fewer sampling points and to permit a definitive traverse of the exhaust gas
-------
Allison
signature at the rear of the engine.
sampling:
Carbon balance computations proved the validity of the
Carbon in = carbon out
Measured fuel and air = measured CO. C02' and HCx in exhaust concentration within ~g %
The details of the analysis are described under the Sampling Quality heading in Section IV.
Sample flow control was difficult until after the high temperature bellows pump was delivered.
This pump. installed in the sample line. isolated the instruments so that the flows were no
longer sensitive to the engine operating conditions. Instrument flows were then easily held
over the engine power range. However. the practice of taking grab samples between readings
of the on-line system was established to reduce the number of adjustments at each of the in-
struments. The long run periods and the duplication of run points in the PTS made this pos-
sible.
Sample line temperatures were easily maintained by the use of Variacs to control the elec-
trical heating tapes. No changes in settings were required once the Variac settings were de-
termined. The heated sample line gas temperature was maintained at 300 :!:lO°F throughout
the test.
Carbon Monoxide and Carbon Dioxide
CO and C02 instruments were stable and the measurements were repeatable throughout the
test. However. the instrument response was low because they were connected in series be-
hind the long-path NO instrument. Maximum values of CO occurred at LSGI; minimum values
occurred at takeoff. C02 concentration was directly proportional to engine fuel/air ratio.
Average concentration values were:
CO (ppm vol)
C02 (% vol)
Low speed ground idle
Ground idle
Takeoff
377
57
37
2.86
1.59
4.55
Repeatability of the instruments is illustrated by the values obtained during repeat runs of the
same engille:
-------
"' Allison
-
Engine 108517-Takeoff power
co (ppm vol) C02 (% vol) Fuel flow (lb/hr)
32 4.98 2150
30 4.93 2150
39 4.90 2150
Oxides of Nitrogen
The LIRA long-path infrared analyzer produced NO readings with obvious variations. Instru-
ment noise and susceptibility to water vapor were two observed problems. Considerable ef-
fort was made to eliminate water vapor by traps and by the use of phosphorous pentoxide
"Aquasorb" drier cartridges, several dozen of which were consumed during the testing.
Typical maximum and minimum values of observed NO (in ppm vol) were:
Minimum (ground idle)
Maximum (takeoff)
118
138
139
114
160
150
152
150
164
153
40
37
21
24
29
32
30
46
24
31
The Saltzman wet chemistry process was run in conjunction with the LIRA NO analyzer on
Engine 108513 to obtain the comparative values of NO and NO plus N02. A comparison of
LIRA and Saltzman showed the N02 content to be about 1/3 of the total NOx content in the ex-
haust at idle:
Saltzman LIRA N02
NO + N02 NO (by subtraction)
Power setting (ppm vol) (ppm vol) ppm vol ..JL.
Low speed ground idle 35 23 12 34
Ground idle 34 21 13 38
Flight idle 51 37 14 27
75% normal 89 66 23 26
100% normal 126 89 37 28
Takeoff 139 123 16 12
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Allison
However, as the engine power is increased, the percentage of N02 is reduced.
The chemiluminescent instrument (Cn was furnished by EPA for this test. A comparison of
values obtained by the LIRA and the CI instruments follows.
Power setting
Low speed ground idle
Ground idle
Flight idle
75% normal
100% normal
Takeoff
LIRA CI CI CI
NO NO NO + N02 N02
(ppm vol) (ppm vol) (ppm vol) (ppm vol)
20 17 25 8
38 22 28 6
24 20 26 6
32 31 38 7
34 33 38 5
68 68 73 5
107 100 107 7
111 107 115 8
107 115 120 5
102 111 118 7
Agreement between the LIRA and CI instruments is within 10% in most cases. The CI instru-
ment measures considerably less N02 in the exhaust (27% at LSGI and 6% at TO) than the
Saltzman method.
Performance and operation of the CI instrument were excellent. It was easy to use, stable,
and fast acting. A comparison of the CI and the 38-in. cell LIRA response is shown in Figure
3-21, which is plotted from the strip chart data for each instrument.
Hydrocarbons
Unburned hydrocarbon readings were close to background levels over most of the engine oper-
ating range. Background was reduced by washing the lines with solvent and back purging the
heated lines until values at the start of a test run were below 20 parts per million carbon
(ppm C). By the time the run was completed, levels were often doubled or trebled. Net
values were determined by introduction of the calibrating gases at the '">robe-to- sample line
connector. Average hydrocarbons were observed as:
-------
Allison
Power setting
Average HCx
(ppm C vol)
Low speed ground idle
Ground idle
Takeoff
367
15
6
Aldehydes
Oxygenated compO\mds as measured by the MBTH method showed low levels (less than 1 ppm)
except at LSGI which was measured at 3 ppm. All levels less than 1 ppm were reported as
one rather than zero. The method is laborious, requiring five minutes to obtain a sample,
and does not appear to give acceptable sensitivity below 1 ppm. However, no better methods
are known at this time.
Flight idle to Takeoff
130
120
-N02 - CI (TECO)
110
40
100
a 90
g.
g. 80
I
N
~ 70
+
~ 60
50
30
o
20
40
Time-seconds
60
80
7200-21
Figure 3-21. T56-A-15 emission transient data (Engine 108517).
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Allison
Smoke
Good agreement in smoke measurements throughout the test is attributed in part to the large
number of sampling points. Smoke values ranged from SIN 41 at LSGI to a maximum single
reading of 62 at flight idle. Generally, smoke values were nearly constant over the flight
range with the maximum at takeoff. Average values were:
Power setting
SIN
Low speed ground idle
Flight idle
Takeoff
42
54.5
56
Particulates
Particulate measurements are arduous, expensive, and impractical to make on production en-
gines. Measurements had been made prior to this program on experimental engines with the
following results. The method used has been the subject of much discussion because of the
unknown character of the material in a water-soluble leg. In these tests, the volumes in each
leg at LSGI and TO were:
Distribution
Power setting H20 soluble (%) HCx soluble (%) Insoluble (%)
LSGI 45 37 18
TO 29 32 39
Comments concerning this method and the questionable significance of the results it produces
were made by the Coordination Research Council in their report on measurement techniques."
Transients
Starting transients were evaluated by integration of the concentration-time curves of Figures
3-13, 3-14, and 3-15. The results for Engine 108518 were:
Concentrations (ppm see)
Hot start Cold start Hot start
CO
HCx
NO
62,400
59,200
3,000
60,000
52,000
2,240
56,800
32,400
2,120
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Allison
The CO and NO measurements are dry-i. e., without correction for water in the exhaust.
An electrical spike (noise) was observed at the onset of transients from all the LIRA instru-
ments. No explanation is attempted for this phenomenon but it is mentioned to avoid antici-
pated problems if results were linked directly into computers from this type of instrument.
Acceleration and deceleration transient values were small- essentially a blending between the
two power levels-as shown in Figures 3-16 through 3-20. This is typical of most aircraft
turbine engines where control of the acceleration and deceleration fuel schedule is precise.
A comparison of transient mass emissions with those of the steady-state LTO cycle is given
in Section IV, Analysis.
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.Allison
-
IV . ANALYSIS
GENERAL APPROACH
Equipment was providld to carefully monitor exhaust gas composition of T56-A-15 production
engines during the production test schedule operation. A matrix of data consisting of operating
variables of the engine and gas compositions was obtained at various levels of engine power.
These raw observations were converted into corrected values (e. g., from dry LIRA measure-
ments to actual basis), and correlating (regression) equations which express pollutant concen-
trations as functions of engine operating variables were determined. Applicable correlating
equations were then used to compute pollutant concentrations for each mode of the required
LTO mission defined subsequently under the LTO Cycle heading. The approach taken here en-
ables computation of the pollutant values of CO, HCx' NOx' and C02 over the entire T56-A-15
engine range of sea level operations.
Summary tables are provided which display pollutant values over the LTO mission in various
units. Mean values of each component are computed along with their associated standard de-
viations.
ENGINE TEST CYCLES
The engine was run over a production. test specification (PTS) schedule during acceptance test-
ing. Data thus obtained were converted to the emission test cycle (Landing-Takeoff or LTO
cycle) which was supplied by Detroit Diesel Allison based on T56 (Model 501) service experi-
ence.
PTS Cycle
In order to obtain emission data without interfering with contractual engine production obliga-
tions, measurements were taken during normal acceptance testing according to the PTS. The
schedule and sequence varies slightly, depending on whether the initial or final run of the ac-
ceptance test is being made. A teardown inspection is made between the initial and final runs.
Emissions measurements were made only during the power" calibration portion of the test
which was run after control adjustments, leak checks, and seal break-in runs, therebyensur-
ing that the measurements were made from engines that had demonstrated acceptable perfor-
mance. The PTS schedule for the T56-A-15 engine final runs is illustrated in Figure 4-1.
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Allison
r-.. 2000
0 Maximum Maximum
I
~.-..
",,"" Accel
=' c::
....~ Military
f II)
~ S 1900 Decel
e U 100% norm
~ e
""Po Go to reverse
.... ""
~CIO for 1 min
C::M
.... co 1800 (15300F max TIT)
QlM
C::""
.... --
.0
"" Accel
=' Accel
Eo< 1700 Decel
75% norm
1600
Decel
Flight idle
/ (1 min)
Ground idle
(2 min)
[ 14000
""
.J, 13000
~
~
Po
II) 12000
QI
bD
c::
f 11 000
~
-
~ 10000
Accel
-Ground idle
Flight idle
Accel to
ground idle
Accel
Shutdown
Shutdown
Low speed ground idle (LSGI)
Start to LSGI
10
40
2 min
Start to LSGI
60
o
20
30
50
Time - minutes
7200-22
Figure 4-1. T56-A-15 production test specification run schedule.
L TO Cycle
A short study of the operational profiles of T56 (50 I)-powered aircraft in the airport environ-
ment was made by the Detroit Diesel Allison Service Department. Only the L-I00 and L- 382
Hercules, the L-188 Electra, and the Convair 580 were considered. The study was also
limited to normal airline operations in North America, to a standard day, and to maximum
allowable operating weights of the aircraft. Only those operations below 3000 ft above terrain
were considered. The resulting profiles were quite similar and were combined into an LTO
cycle representative of a Model 501 turboprop engine-powered aircraft.
Taxi-idle operations were specifically reviewed in detail because of the relatively large mass
emissions contribution of the low speed ground idle (LSGI) power point which is run at 10,000
rpm with the compressor bleeds open. It is used whenever the aircraft is held stationary on
the ramp or at the dock. The LTO cycle evolved from the study is summarized in Table 4- I.
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Allison
Table 4- I.
Representative landing-takeoff cycle for Model 501 turboprop aircraft.
Turbine Fuel
Mode Mode time Engine Engine inlet temp flow Fuel/air
No. Mode description (min) power rpm (OF) (lb/hr) ratio
1 Holding- outbound 4.0 Low speed 10,000 1200 565 0.013
ground idle
2 Taxi-outbound 2.0 High speed 13,500 1070 670 O. 0075
ground idle
3 Takeoff 0,5 Takeoff 13,800 1970 2175 O. 0225
4 Climb out 2.5 Near 90% 13,800 1850 1870 0.019
normal
5 Approach 4. 6 Near flight 13,800 1200 860 0.010
idle
6 Reverse 0.167 Reverse 13,800 1610 1390 0.0155
7 Holding-inbound 4,0 Low speed 10,000 1200 565 0.013
ground idle
8 Taxi- inbound 2.0 High speed 13,500 1070 670 0, 0075
ground idle
DA T A ANALYSIS
An overall schematic diagram of the data handling process used herein is illustrated in Figure
4-2.
General Preparation
Test programs pose inherent problems in acquiring complete sets of data, Mechanical mal-
functions, instrument failure, operators, etc, all contribute to potential data matrix gaps.
Subsequently, these gaps cannot be ignored, nor can zero be substituted in the matrix in lieu of
data, Therefore, the missing data items were filled with reasonable and expected quantities to
complete the data matrix. This procedure was incorporated during the raw data conversion.
However. in retrospect, the effects of this device were found to be completely submerged by the
natural dispersion of the whole data population.
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.Allison
Measure pollutant
concentrations and
engine operating
variables on test stand
over PfS cycle
!
Enter appropriate values
on input data format
and punch raw data
on cards
!
Program OSEPAI
Read raw data
Convert units
Convert to wet basis
Punch out rearranged data
in format required by
regression deck
J
Sequential Regression Analysis Deck
Compute least square-fitted nonlinear
regression coefficients for each component
versus four engine operating parameters
Compute measure of goodness of fit and
coefficient of determination
!
Program OSEPA2
Compute pollutant concentrations in each
mode of LTO cycle and sum over all modes
Write final summary tables
7200-23
Figure 4-2.
Schematic diagram of data handling process.
Regression Analysis
Preliminary examination of the raw data early in the effort showed that the following engine
parameters were the only ones required in the nonlinear regression equations considering the
sample size and quality of measurements. The independent variables, then, are:
. Turbine inlet temperature (TIT)
. Fuel/air ratio (F/A)
. Output horsepower (HP)
. Reciprocal horsepower (1 /HP)
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Allison
"'On.
,;:E.=.."'.:,J
It follows that any pollutant concentration, y, is expressable in terms of these independent
variables by a regression equation of the form:
y = Al+A2'TIT + A3.F/A + A4.HP + A5/HP
(1)
The coefficients in Equation (1) are unique for each component in each engine.
In order to define the required independent variables, the measurements shown in Table 4-n
were observed for each engine and entered on the raw data input format. Because of the con-
stant- speed characteristics of the T56 engine, total engine airflow in pounds per second can
be defined for all test points except LSGI by specifying compressor air inlet temperature and
ambient pressure at the engine air inlet test bell.' Appendix D gives these airflow values.
For the 10, OOO-rpm LSGI operating point, airflow (Wa) was defined by Equation (2):
Wa = 22.1566 - 0.001244 (459. 74 + TIT)
(2)
Horsepower was computed in the standard manner as shown by Equation (3):
HP = 0.158682. iTORQ. iRPM.
(3)
Observed concentrations from the raw data (corrected to wet basis in the case of CO, NOx'
and C02) were then fed into the sequential regression analysis step where all the regression
coefficients, Ai, of Equation (1) were computed using an algorithm described by M. A.
Efroymson. iii For each regression Equation (1), a quantity labeled S(y) is produced which may
be approximately interpreted as the :i: one- sigma band on the computed values of concentrations
from Equation (1). It should be emphasized that the regression equations defined herein play
a dual ~ in the analysis. First, they serve to show how sensitive a given concentration is
to each of the engine variables (TIT, F I A, HP, or 1/HP). Second, they serve as smoothing
and interpolating functions for pollutant concentrations at operating points other than those ob-
served in the raw data. This latter property is essential since the raw measurements were
made at points in the space (TIT, F/A, HP) which do not correspond with points required for
the LTO mission cycle. Appendix E is a listing of all regression coefficients, Ai' for all
components measured on all engines in addition to S(y) for each case, and N-the number of
observations used in the particular regression. The column labeled R2 contains values of the
coefficient of determination for each regression. The square root of R 2 is the coefficient of
multiple correlation. Commonly, R2 is referred to as the fraction of variation in the observed
values of the dependent variable which is accounted for by the given regression equation. An
R2 value of 1.0 implies a perfect functional fit.
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Allison
Table 4- II.
Dictionary of raw input data.
FORTRAN
label Format Description Unit
-
mATE i3 Date of measurement (e. g.. 716 means July 16) none
iENG i4 Last four digits of engine serial number none
GF i1 Label G or F denoting "green" run on engine or "final" none
run on engine
iSET i2 Setting number of engine test cycle none
iRPM i3 RPM/100 rpm/100
iWF i4 Fuel flow lb/hr
iTORQ i3 Actual engine torque /1 00 in. -lb/100
iTIT i4 Turbine inlet temperature of
iCIT i3 Compressor inlet temperature of
iHUM i2 Relative humidity of inlet air %
iCO i4 Measured CO concentration (dry basis- LIRA) ppm vol
iC02 i3 Measured C02 concentration (dry basis- LIRA) % vol X 100
iNOl i3 Measured NOx (as N02) (dry basis- LIRA) ppm vol
iHCx i4 Measured HCx (as C) (as-is basis- FID) ppm vol
iSMOK i2 Measured smoke index (smoke number-SIN) none
iCHO i4 Measured aldehydes as formaldehyde ppm vol
iSALT i3 Measured NOx (as N02) by Saltzman wet method ppm vol
iN02 i4 Measured NO (as NO) by chemiluminescent analyzer ppm vol
iNON02 i4 Measured total NO + N02 by chemiluminescent analyzer ppm vol
iPRES i3 Ambient barometric pressure in. Hg X 10
The conversion of dry concentrations to the wet basis is made using equations and procedures
recommended by an SAE study committee.1 These are given in Appendix C.
RESULTS
Final summary results for the regression analysis for each of the eleven engines are given in
this subsection. Carbon dioxide values are computed to lend confidence to the quality of ex-
haust gas sampling and to show combustion efficiency.
Concentrations computed from regression equations for LTO points may occasionally be nega-
tive, so logic has been incorporated into the computer program to set such values to zero be-
cause negative weights are clearly not admissible.
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.Allison
~-".....,
Regression Analysis
All regression coefficients, Al through A5' the pseudostandard deviation, S(y), the coefficient
of determination, R2, and the number of observations, N, on each engine examined are sum-
marized in Appendix E.
R2 values for C02 regressions are always extremely high because C02 must correlate well
with fuel/air ratio. The other components-CO, HCx' smoke, and NOx-nearly always have
R2 values well above 0.9. R2 values from Engine 108512 illustrate this. Dispersion values,
S(y), are typically about what one might expect from analytical errors of the measuring instru-
ments.
Component R2
C02 0.999998
CO 0.978
HCx 0.959
Smoke 0.976
NOx 0.898
LTO Computation
Table 4-IU shows the basic mass emission performance for each T56 engine. All other sum-
mary tables are derived from this master. Pollutants CO, NOx' HCx' and C02 are each re-
ported three ways for each mode of the mission-viz:
. Ib/l000 lb fuel (LB/TPF)
. lb/hr
. lb for mode
The columns of pounds in mode are then summed over all modes to give measured pounds
pollutant over the whole eight-mode mission. One such table is printed for each engine.
The results of Table 4-nI are condensed in Table 4-IV which lists total pounds of each pollu-
tant (over the LTO mission) for each engine. It also gives mean values of pounds of pollutant
over the sample of all engines and the standard deviation of each pollutant from the sample
mean. A second set of means and standard deviations is computed over the deleted sample of
seven engines for which actual ground start mode was measured. In the table, those engines
labeled with an asterisk are those which use the CO, HCx, and NO regressions belonging to
-------
.Allison
Engine 108512 inasmuch as no LSGI data were taken for these units. This arbitrary insertion
of data was done only in the interest of "rOtUlding out" the sample and, as seen in the values
labeled "mean (7)" and ":I: tT (7)" has some effect on the rounded-out sample mean. Note that
all three "mean (7)" values lie well within the one- sigma band of the means over eleven engines.
This suggests that the bias introduced by rounding out is not large and the mean of the sample
of eleven engines is validated.
Table 4- III.
Emission performance summary.
LTO CYCLE T56 ENGINE NUMBER B509
MODE ITIT MODE FUEL ... CO ... ... N02 ... ... HCX ... ... C02 ...
DEG. RPM TIME LBSI L8S1 L8S1 LBS. LBSI LBSI LBS. LBSI L8S1 LBS. LBSI L8S1 LBS.
F MINS. HR TPF HR TPF HR TPF HR TPF HR
1 1200 10000 4.000 565 32.6 IB.4 1.221 3.472 1.962 0.131 14.36 8.12 0.54 3048.2 1722.2 114.B
2 1070 13500 2.000 670 13.9 9.3 0.311 6.814 4.565 0.152 5.22 3.49 0.12 3106.2 2081.2 69.4
3 1970 13800 0.500 2175 1.5 3.3 0.028 10.523 22.888 0.191 0.08 0.17 0.00 3141.9 6833.6 56.9
4 1850 13800 2.500 1870 1.8 3.4 0.11;3 10.971 20.517 0.855 0.11 0.20 0.01 3141.3 5874.2 244.8
5 1200 13800 4.600 860 0.5 0.4 0.034 7.870 6.768 0.519 0.0 0.0 0.0 3143.7 2703.6 207.3
6 1610 13800 0.167 1390 1.6 2.3 0.0(6 10.116 14.062 0.039 0.0 0.0 0.0 3141.9 4367.3 12.2
7 1200 10000 4.000 565 32.6 18.4 1.227 3.472 1.962 0.131 14 .36 8.12 0.54 3048.2 1722.2 114.8
8 1070 13500 2.000 670 13.9 '1.3 0.3H 6.814 4.565 0.152 5.22 3.49 0.12 3106.2 2081.2 69.4
TOTAL CO 2 3.287 TOTAL NOX 2 2.170 TOTAL HCX m 1.325 TOTAL C02 = 889.5
LTO CYCLE T56 ENGINE NUMBER 8516
MODE !TIT MODE FUEL .... CO ... ... N02 ... ... HCX ... .... C02 ...
DEG. RPM UHE LBSI L8S1 LBSI LBS. LBSI LBSI LBS. LBSI LBSI LBS. LBSI LBSI LBS.
F MINS. HR TPF HR TPF HR TPF HR TPF HR
1 1180 10000 4.000 560 29.0 16.2 1.083 0.116 0.401 0.027 14.90 8.34 0.56 3052.1 1709.2 113.9
2 1070 13500 2.000 1>70 9.9 6.6 0.221 6.137 4.111 0.137 1.23 0.82 0.03 3125.1 2093.8 69.8
3 1970 13 800 0.500 2175 5.3 11.5 0.096 10.859 23.618 0.197 1.92 4.18 0.03 3130.2 6808.1 5/0.7
4 1850 13800 2.500 1870 1.4 2.6 0.110 8.354 15.621 0.651 0.22 0.42 0.02 3141.6 5874.8 241t.B
5 1200 13800 4.600 B60 501 4.4 ~.338 5.626 4.838 0.371 0.02 0.02 0.00 3136.4 2697.3 206.8
6 1610 13800 0.167 1390 1.5 2.0 0.006 5.741 7.979 0.022 0.15 0.21 0.00 3141.7 4367.0 12.2
7 1180 10000 4.000 560 29.0 16.2 1.083 0.116 0.401 0.027 14.90 8.34 0.56 3052.1 1709.2 113.9
8 1070 13500 2.000 670 9.9 6.6 0.221 6.137 4.111 0.137 1.23 0.82 0.03 3125.1 2093.8 69.8
TOTAL CO 2 3.157 TOTAL NOX = 1.51>8 TOTAL HCX 2 1.221 TOTAL C02 m 887.9
LTC CYCLE T5/o ENGINE NUM8ER 8518
MODE ITIT MODE FUEL .... CO .... ... N02 ... ... HCX ... ... C02 ...
DEG. RPM TINE LBSI LBSI LBSI LBS. LBSI LBSI LBS. LBSI LBSI LBS. L8S1 L8S1 L8S.
F "INS. HR TPF t'R TPF HR TPF HR TPF HR
1 1160 10000 4.000 560 25.5 14.3 0.952 4.229 2.36B 0.158 14.67 8.21 0.55 305B.3 1112.7 114.2
2 1070 13500 2.000 1>70 7.9 5.3 0.177 5.5'i17 3.750 0.125 0.45 0.30 0.01 3130.6 2097.5 69.9
3 1970 13800 0.500 2175 2.3 5.0 0.041 B.037 17.4BO 0.146 0.75 1.62 0.01 3138.6 6826.1t 56.9
4 1850 13800 2.500 1870 0.4 0.7 0.028 8.528 15.948 0.664 0.0 0.0 0.0 3144.0 5879.2 245.0
5 1200 13800 4.600 860 3.2 2.7 0.210 6.176 5.311 0.407 0.0 0.0 0.0 3139.5 2100.0 207.0
6 1610 13800 0.167 1390 1.0 1.4 0.00"" 8.054 11.195 0.031 0.0 0.0 0.0 3142.9 4368.7 12.2
7 1160 10000 4.000 560 25.5 14.3 0.952 4.229 2.368 0.158 14.67 8.21 0.55 3058.3 1712.7 114.2
8 1070 13 500 2.000 670 7.9 5.3 0.177 5.591 3.750 0.125 0.1t5 0.30 0.01 3130.6 2097.5 69.9
YOTAL CC = 2.542 TOTAL NOX = 1.814 TOT AL HCX = 1.129 TOTAL C02 2 889.2
l TQ CYCLE T56 ENGINE NUMBER 8512
MOOE ITIT MODE FUel ... to ... ... N02 ... ... HCX ... ... t02 ...
DEG. RPH TIME L8S1 L8S1 L8S1 L8S. L8S1 L8S1 LBS. LBSI LBSI LBS. LBSI LBSI LBS.
F MINS. HR TPF HR TPF HR TPF HR TPF HR
1 1200 10000 4.0CO 554 27.3 15.1 1.008 1.323 0.733 0.049 12.31 6.82 0.45 3062.9 1696.9 113.1
2 1070 13500 2.000 670 12.0 8.0 0.267 7.054 4.726 0.158 2.38 1.59 0.05 3118.2 2089.2 69.6
3 1970 13800 0.500 2175 3.9 8.6 0.072 7.603 16.538 O. 138 1.46 3.17 0.03 3133.7 6815.9 56.8
4 1850 13800 2.500 1870 2.4 4.5 O. 1 e 7 8.688 16.247 0.677 0.36 0..8 0.03 3139.6 5871.1 21t4.6
5 1200 13800 4.600 860 5.7 4.9 0.376 4.787 4.117 0.316 0.38 0.. ) 0.03 3134.4 2695.5 206.7
6 1610 13800 O. 167 1390 3.1 4.3 0.012 7.447 10.351 0.029 0.31 0.43 0.00 3138.7 1t362.7 12.1
7 1200 10000 4.000 554 27.3 15.1 1.008 1.323 0.733 0.049 12.31 6.82 0.45 3062.9 1696.9 113.1
8 1070 13500 2.000 1>70 12.0 8.0 0.267 7.054 4.726 0.158 2.38 1.59 0.05 3118.2 2089.2 69.6
TOTAL to = 3.198 TOTAL NOX ~ 1.572 TOTAL HtX = 1.096 TOTAL t02 = 885.8
-------
Allison --
Table 4-Ill. (cont)
LTO CYCLE T56 ENGINE NU~BER 8513
"DOE iT IT MOOE FUEL ... CO ... ... N02 ... ... HCX ... ... C02 ...
OEG. liP" TI"E l' ~! lBS! l8S! lBS. lBS! lBS! LBS. lBS! lBS! LBS. lBS! lBS! lBS.
F "INS. t.'1 TPF I4 21>.0 14.1 0.911 3.155 2.ll8 0.141 12.80 1.22 0.48 3063.4 1721.8 ll5.2
2 1010 13500 2.000 1>10 5.3 3.1> 0.119 3.31>3 2.253 0.015 0.0 0.0 0.0 3131>.1 2101.2 10.0
3 1910 13800 0.500 2115 2.4 5.3 0.044 8.411 18.431 0.154 0.0 0.0 0.0 3140.1 1>831.1 51>.9
4 1850 I. 3800 2.500 1810 0.0 0.0 0.0 8.859 16.51>1 0.1>90 0.0 0.0 0.0 3144.5 5880.2 245.0
5 1200 13800 4.1>00 81>0 4.8 4.1 0.318 4.892 4.201 0.323 0.08 0.01 0.01 3131>.1 2691.1> 206.8
I> 1610 13800 0.11>1 1390 1.3 1.8 0.005 B.008 ll.l31 0.031 0.0 0.0 0.0 3142.4 4368.0 12.2
1 1210 10000 4.000 51>4 21>.0 14.1 0.911 3.155 2.ll8 0.141 12.80 1.22 0.48 301>3.4 1721.8 115.2
B 1010 13500 2.000 610 5.3 3.1> 0.119 3.31>3 2.253 0.015 0.0 0.0 0.0 3131>.1 2101.2 10.0
TOTAL CO.. 2.559 TOTAL NOX" 1.1>30 TOTAL HCX" 0.91>8 TOTAL C02 a 8'n.4
lTO CYCLE T56 ENGINE NU"BER 8501>
"ODE IT IT MODE FUEL ... CO .... ... N02 ... .... HCX ... ... C02 ...
OEG. RPM TI"E lBS! lBSI lBS! lBS. lBS! lBS! lBS. l8S! lBS! lBS. lBSI lBS! lBS.
F "INS. HR TPF HR TPF HR TPF HR TPF HR
1 1200 10000 4.000 51>5 21.3 15.4 1.029 20.121 11.107 0.180 12.33 1>.96 0.41> 301>2.8 1130.5 115.4
2 1070 13500 2.000 1>10 12.0 8.0 0.21>1 10.521 1.053 0.235 2.38 1.59 0.05 3ll8.2 2089.2 1>9.1>
3 1970 13800 0.500 2115 3.9 8.6 0.072 12.51>11 21.339 0.228 1.41> 3.17 0.03 3133.1 1>815.9 51>.8
4 1850 13800 2.500 1810 2.4 4.5 0.181 10.4~9 19.1>34 0.818 0.31> 0.1>8 0.03 3139.1> 5811.1 244.1>
5 1200 13 900 4.1>00 81>0 5.1 4.9 0.371> 10.380 8.921 0.1>84 0.38 0.33 0.03 3134.4 21>95.5 201>.7
I> IblO 13800 0.11>1 1390 3.1 4.3 0.012 10.092 14.021 0.039 0.31 0.43 0.00 3138.1 431>2.1 12.1
1 1200 10000 4.000 51>5 21.3 15.4 1.029 20.121 11.101 0.780 12.33 1>.91> 0.41> 301>2.8 1130.5 115.4
8 1070 13500 2.000 1>10 12.0 e.o 0.21>1 10.521 1.053 0.235 2.38 1.59 0.05 3ll8.2 2089.2 1>9.1>
TOTAl CO '" 3.240 TOTAl NO X " 3.800 TOTAL HCX" 1.111> TOTAL C02" 890.2
LTO CYCLE T51> ENGINE NUMBER 8501
"DOE ITIT MODE FUEL ... CO ... ... N02 ... .... HCX ... ... C02 ...
OEG. RPI'! TIME lBSI lBSI lBS! l8S. lBS! lBS! lBS. lBSI l8S! l8S. LBS! lBSI lBS.
F "INS. HR TPF HR TPF HR TPF HR TPF HR
1 1200 10000 4.000 51>5 27.4 15.5 1.031 3.1>83 2.081 0.139 14.04 1.93 0.53 3051.4 1721.4 115.2
2 1010 13500 2.000 610 3.5 2.4 0.078 1.091 4.155 0.158 0.0 0.0 0.0 3139.0 2103.1 10.1
3 1910 13800 0.500 2115 0.4 0.8 0.001 9.232 20.080 0.11>1 0.0 0.0 0.0 3143.9 6838.0 51.0
4 1850 13800 2.500 1810 1.3 2.5 0.104 9.1>78 18.098 0.154 0.0 0.0 0.0 3142.4 5811>.3 244.8
5 1200 13800 4.1>00 81>0 1.1 0.9 0.010 1.581 1>.519 0.500 0.0 0.0 0.0 3142.9 2102.<; 201.2
I> IblO 13800 0.11>1 1390 3.1 4.4 0.012 9.011 12.1>11 0.035 0.04 0.05 0.00 3139.5 4363.8 12.1
1 1200 10000 4.000 51>5 21.4 15.5 1.031 3.1>83 2.081 0 . 139 14.04 7.93 0.53 3051.4 1121.4 115.2
8 1010 13500 2.000 1>10 3.5 2.4 0.078 1.097 4.155 0.158 0.0 0.0 0.0 3139.0 2103.1 10.1
TOTAL CO" 2.413 TOTAL NOX" 2.051 TOTAL HCX. 1.058 TOTAL C02" B91.7
lTO CYCLE T51> ENGINE NU~BER 8510
IIIOOE IT IT MODE FUEl ... CO ... .e. N02 ... .... HCX ... ... C02 ...
OEG. RPI'1 TI IIIE L8S! lBS! l8S! LBS. lBS! lBS! lBS. lBS! lBS! lBS. lBS! lBSI lBS.
F MINS. HR TPF HR TPF HR TPF HR TPF HR
1 1200 10000 4.000 565 21.3 15.4 1.029 17.104 10.003 0.1>1>1 12.33 6.91> 0.41> 3062.B 1130.5 115.4
2 1010 13500 2.000 1>70 12.0 8.0 0.21>1 1>.501> 4.359 0.145 2.38 1.59 0.05 3ll8.2 2C89.2 69.1>
3 1910 13S00 0.500 2115 3.9 8.1> 0.072 8.321> 18.11C 0.151 1.46 3.17 0.03 3133.1 1>815.'1 51>.8
4 1850 13800 2.500 1810 2.4 4.5 0.181 1.81>6 14.110 0.1>13 0.36 0.1>8 0.03 3139.6 5811.1 244.1>
5 1200 13900 4.600 81>0 5.1 4.9 0.311> 4.'>14 3.191> 0.291 0.38 0.33 0.03 3134.4 2695.5 201>.1
I> 11>10 13800 0.11>1 1390 3.1 4.3 0.012 1.141> 9.932 0.028 0.31 0.43 0.00 3138.1 431>2.1 12.1
1 1200 10000 4.000 51>5 21.3 15.4 1.029 11'1C4 10.003 0.1>1>1 12.33 1>.91> 0.41> 3062.8 1130.5 115.4
8 1010 13500 2.000 1>10 12.0 8.0 0.21>1 1>.501> 4.359 0.145 2.38 1.59 0.05 3118.2 2089.2 1>9.1>
TOTAL CO.. 3.240 TO TAL NOX" 2.101 TOTAL Hex.. 1.lll> TOT Al C02" 890.2
lTO CYCLE T51> ENGINE NUM8ER 841>'1
"ODE ITn MOOE FUEL .... CO ... ... N02 ... .... HCX ... ..... C02 ...
OEG. RPI'1 TIME l8S! l8S! lBS! l8S. lBS! lBS! l8S. l8S1 lBSI l8S. l8S! l8S! l8S.
F MINS. HR TPF I5 21.3 15.4 1.029 2.41>1> 1.393 0.093 12.33 6.91> 0.41> 3062.8 1730.5 115.4
2 1010 13500 2.000 610 12.0 8.0 0.21>1 3.511 2.3'17 0.080 2.38 1.59 0.05 3ll8.2 208'1.2 1>9.6
3 1910 13800 0.500 2115 3.9 8.1> 0.012 9.1>4" 20.975 0.175 1.41> 3.17 0.03 3133.1 1>815.9 51>.8
4 1850 13800 2.500 1810 2.4 4.5 0.187 11.181> 20.917 0.872 0.36 0.1>8 0.03 313'1.1> 5811.1 244.6
5 1200 13800 4.1>00 81>0 5.7 4.9 0.311> 4.'122 4.233 0.325 0.38 0.33 0.03 3134... 21>95.5 201>.1
6 1610 13800 0.11>1 1390 3.1 4.3 0.012 10.092 14.021 0.039 0.31 0.43 0.00 313B.1 431>2.7 12.1
1 1200 10000 4.000 565 21.3 15.4 1.029 2.461> 1.3'13 0.093 12.33 1>.91> 0.41> 301>2.8 1730.5 115.4
8 1010 13500 2.000 1>10 12.0 e.o 0.21>1 3.571 2.391 0.080 2.38 1.59 0.05 3118.2 2089.2 1>9.1>
TOTAL ec" 3.240 TOTAL NOX" 1.155 TOT Al Hex" 1.ll6 TOTAL C02" 890.2
-------
Allison
Table 4- ITI.
(cont)
LTC CYCLE T56 ENGINE NUMBER B50B
MODE IT IT MODE FUEL ... CO ... ... N02 ... ... HCX ... ... C02 ...
DEG. RPM TIME LBSI lBSI LBSI LB!.. LBSI LBSI LBS. lBSI LBSI LBS. LBSI LBSI LBS.
F MINS. HR TPF I'R TPF HR TPF HR TPF HR
1 1200 10000 4.000 565 21.3 15.4 1.029 23.151 13.0BO 0.B12 12.33 6.96 0.46 3062.B 1730.5 115.4
2 1010 13500 2.000 610 12.0 8.0 0.267 8.B19 5.909 0.191 2.38 1.59 0.05 311B.2 20B9.2 69.6
3 1970 13800 0.500 2115 3.9 8.6 0.072 12.991 28.268 0.236 1.46 3.11 0.03 3133.1 6815.9 56.B
4 1850 13800 Z.500 1810 2.4 4.5 0.181 12.382 23.155 0.965 0.36 0.6B 0.03 3139.6 5B11.1 244.6
5 1200 13BOO 4.600 860 5.1 4.9 0.316 6.021 5.118 0.391 0.38 0.33 0.03 3134.4 2695.5 206.1
6 1610 13800 0.161 1390 3.1 4.3 0.012 10.840 15.068 0.042 0.31 0.43 0.00 3138.1 4362.1 12.1
1 1200 10000 4.000 565 21.3 15.4 1.029 23.151 13.080 0.872 12.33 6.96 0.46 3062.8 1130.5 115.4
8 1070 13500 2.000 610 12.0 8.0 0.261 8.819 5.909 0.191 2.38 1.59 0.05 3118.2 2089.2 69.6
TOTAL CO = 3.240 TOTAL NOX = 3.111 TOTAL HCX = 1.116 TOTAL C02 c 890.2
LTO CYCLE T56 ENGINE NUMBER 8511
"ODE IT IT MODE FUEL ... CO ... ... N02 ... ... HCX ... ... C02 ...
DEG. RPI'! UME lBSI 1.8S1 L8S1 L8S. lBSI lBSI lBS. LBS! lBS! lBS. LBSI lBS! LBS.
F "INS. HR TPF HR TPF HR TPF HR TPF HR
1 1140 10000 4.000 5B6 18.6 10.9 0.126 2.263 1.326 0.088 10.4B 6.14 0.41 3082.4 lB06.3 120.4
2 1070 13500 2.000 610 9.9 6.6 0.221 5.240 3.511 0.111 2.40 1.61 0.05 3121.4 2091.4 69.1
:3 1970 13800 0.500 2115 1.0 2.3 0.019 7.830 11.030 0.142 0.0 0.0 0.0 3142.9 6835.8 51.0
4 1850 13BOO 2.500 1810 0.4 C.1 0.028 B.l11 15.280 0.631 0.0 0.0 0.0 3144.0 5819.2 245.0
5 1200 13800 4.600 860 2.1 1.8 0.139 5.959 5.124 0.393 0.0 0.0 0.0 3141.2 2101.4 201.1
6 1610 13800 0.161 1390 0.5 0.8 0.002 1.559 10.506 0.029 0.0 0.0 0.0 3143.1 4369.1 12.2
7 1140 10000 4.000 586 18.6 10.9 0.126 2.263 1.326 0.088 10.48 6.14 0.41 3082.4 1806.3 120.4
8 1070 13500 2.000 610 9.9 6.6 0.221 5.240 3.511 0.111 2.40 1.61 0.05 3121.4 2091.4 69.7
TOTAL CO c 2.0Bl TOTAL NOX c 1.612 TOTAL HCX '" 0.926 TOTAL C02 '" 901.5
Table 4- IV .
Summary of pOWlds of pollutants over the LTO mission for individual T 56 engines.
POWlds pollutant
Engine No. CO NOx HCx C02
108506* 3.24 3.80 1.12 890.2
108509 3.29 2.17 1.33 889.5
108516 3.16 1.57 1.22 887.9
108518 2.54 1.81 1.13" 889.2
108512 3.20 1.57 1.10 885.8
108513 2.56 1.63 0.97 891.4
108517 2.08 1.61 0.93 901.5
108508* 3.24 3.78 1.12 890.2
108507 2.41 2.05 1.06 891.7
108510':' 3.24 2.71 1.12 890.2
108469'~ 3.24 1.76 1.12 890.2
Mean (11) 2.93 2.22 1.11 890.7
:f: u (11) 0.44 0.85 0.11 3.9
Mean (7) 2.75 1.77 1.11 N/A
:f: CT (7) 0.47 0.25 0.14 N/A
*Based on Engine 108512 regression (see text).
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Allison
-
Listed in Table 4- V are the pounds of pollutants per one thousand pounds of fuel for each
pollutant for each engine.
Table 4- VE is a summary of pounds of pollutants per minute and pounds of pollutants per pound
of fuel in each mode, o.veraged over all eleven engines. As in other tables, the data for Table
4-VI were taken from Table 4-m.
Table 4- V .
Summary of pounds of pollutants per thousand pounds of
fuel over the LTO mission for individual T56 engines.
Engine No.
108506*
108509
108516
108518
108512
108513
108517
108508*
108507
108510*
108469*
Mean
Mean % of total
:t:cT
f: fT % of mean
Pounds pOllutant/l000 lb fuel
CO NOx HCx Total
11.4
11.5
11.1
8.9
11.2
9.0
7.3
11.4
8. 5
11.4
11.4
10.3
46.8
1.5
14.5
13.3
7.6
5.5
6.4
5.5
5.7
5.7
13.2
7.2
9.5
6.2
7.8
5.5
2.9
37.0
3.9
4.6
4.3
4.0
3.8
3.4
3.3
3.9
3.7
3.9
3.9
3.9
17.7
0.4
10.3
28.6
23.7
20.9
19.3
20.5
18.1
16.3
28.5
19.4
24.8
21.5
22.0
100. 0
4.0
*Based on Engine 108512 regression (see text).
Sampling Quality
It was necessary to provide representative means to sample the T56 exhaust gas. The sampling
probe and lines have been discussed previously but here evidence is presented based on a car-
bon balance which indicates that sampling was very representative and that analytical results
are consistent. For example, consider the data from Engine 108516 as reported in Table 4-nr.
The theoretical value of pounds of C02 per 1000 pounds of fuel (H/C ratio = 1. 97) is given by
1000 X 44.011
= 3144.4.
12.011 + 1.97 X 1. 008
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Allison
Table 4- VI.
Rate of formation of pollutants averaged over all engines for
each mode of the LTO cycle.
Mode Pounds pollutant/min X 100 POW1ds pollutant/pound of fuel
No. Description CO NOx HCx CO NOx HCx
1 LSGI 25.3 7.2 12.2 26.9 7.6 13.0
2 GI 11.2 7.2 2.1 10.0 6.4 1.9
3 TO 10.8 33.2 3.4 2.9 9.6 0.9
4 Climb 4.9 29.8 0.7 1.6 9.6 0.2
5 Approach 5. 9 8.9 0.4 4.1 6.2 0.2
6 Reverse 5.1 19.8 0.0 2.2 8.6 0.2
7 LSGI 25.3 7.2 12.2 26.9 7.6 13.0
8 GI 11.2 7.2 2. 1 10.0 6.4 1.9
Table 4- vn shows the final corrected values of pounds of CO. HCx. and C02 per thousand
pounds of fuel. together with computed values of C02 after converting measured CO to C02
and measured HCx to C02. The CO and HCx values are converted to equivalent C02 by
44.011
CO X = equivalent C02 from CO
28. 01
44. 011
HCx X 13.981 = equivalent C02 from HCx
Table 4- VII.
Carbon balance results from Engine 108516 in LTO cycle.
(Concentrations are pounds pOllutant/lOOO lb fuel)
Total
Mode CO HCx C02 C02
1 29.0 14.9 3052. 1 3144.6
2 9.9 1023 3125. 1 3144.5
3 5.3 11.92 3130.2 3144.6
4 104 0.22 3141.6 3144. 5
5 5. 1 0.02 3136.4 3144.f
6 10 5 0.15 3141.7 3144.5
7 29.0 14.9 3052. 1 3144.6
8 9.9 1.23 3125.1 3144. 5
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-
Considering the fact that CO, HCx' and C02 are measured on independently calibrated analyzers
and the total C02 values of Table 4- vn are so close to the theoretical value of 3144.4, it was
concluded that the sampling was representative and the analyses are good. Moreover, the re-
gression equations provide very good interpolations, at least in this case.
Smoke Index * Correlations
A careful examination of the raw smoke index measurements shows that the span of index values
for Engines 108506, 108508, 108510, and 108469 is so small as to render them essentially con-
stant and thus show poor correlation against the independent variables. When these engines
are removed from the sample, all the remaining engines have high R2 values and, except for
Engines 108509 and 108516, smoke index correlates well with I/HP by a regression equation
of the form:
SMOK = a - b/HP
Figure 4-3 illustrates this behavior for Engine 108518. Note the S(y) bands on either side of
the regression line. It would be highly desirable to have more low- power smoke index values.
Engine 108518 displayed regression: smoke = 56.0 - 1245/hp :I: 1
-
---
----
---
50
./'
~./'
7/
II
If
o -
--.
---
--
o
~
55
~
z
.......
In
-; 45
'"
"
.S
'"
.:.:
o
e
en 40
S(y) hp Smoke
(;:: :1:"')
95 42
236 52
236 52
765 54
. 765 54
2672 54
3679 55
3985 56
4248 56
4248 56
4270 56
35
30
o
500
1000
1500
2000
2500
3000
3500
Horsepower
7200-24
Figure 4-3. Smoke index VB power.
*
Or Smoke number (SIN)
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Allison
Aldehyde Measurements
Aldehydes were measured by a wet chemical method for each setting of Engine 108517. All
observations were at the limit of detection of the method-viz, less than 1.0 ppm formaldehyde-
except the value at ground start which was 3.0 ppm. No statistical observations are possible.
Particulates
The particulate values reported in Section III were used to compute the particulate emission
index which is given in Table 4- VIII. No statistical analysis was possible because of the small
number of data points.
Table 4- VIll.
Particulate emission rates.
(LACAPCD impingers-JP- 5 fuel)
LTO Power Particulates
mode setting (lb /1 000 lb fuel)
1 LSGI 18.1
2 GI 21.7
3 TO 5.34
4 Climb 8.96
5 Approach 16.3
6 Reverse 10.7
7 LSGI 18. 1
8 GI 21.7
COMMENTARY
Variability of Results
The variability of the mass emissions was computed for the LTO mission (Table 4-IV) for the
eleven engines tested, Expressed in percent of total mass for the entire LTO, these are:
Pollutant CO NOx HCx C02
Mean wt, lb 2. D3 2.22 1. 11 880.7
:f: fT, lb 0.44 0.B5 O. 11 :i. !)
:f: fT as percent of mean wt 15.0 38.0 10.0 0.43
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Three known sources contribute to this variability, none of which could be evaluated separately
during this series of tests:
. Measurement error
. Engine variations
. Analytical variance
The general performance of the measurement system and problems contributing to measure-
ment error are discussed in Section ITI. The largest data scatter occurred at low concentra-
tion levels. It is expected that the contribution to variability of these points might be con-
siderable.
True performance variations existed over the eleven engines tested and are illustrated by the
variability in brake specific fuel consumption of the engines tested for emissions:
Avg BSFC = 0.5044
Lowest BSFC = 0.4950
Highest BSFC = 0.5110
All of the preceding data were corrected to standard inlet conditions.
Emissions performance variations also undoubtedly exist but could not be evaluated statistically
with the small number of engines sampled. Improved measurement accuracy, good statistical
knowledge of that accuracy, and an adequate sample size are required before a finite value of
engine-to-engine variation can be obtained.
The emission tests in this program were run over a production test cycle. Conversion of these
data to the LTO emissions test cycle required interpolation of data which was done with regres-
sion techniques to minimize interpolation error. Nevertheless, until the emissions test cycles
are run directly, some error in converting data will occur.
L TO Cycle
The use of a landing-takeoff operational cycle as a means to evaluate the emissions from air-
craft engines could impose large bias values, depending on the time assumed for each opera-
tional mode. The influence of time in mode and emission rates is illustrated in Figure 4-4.
In this chart. the mean rates of mass emissions are represented by the bar height and the time
in mode by the bar width. The area is the mass emissions in the mode. The extreme influence
of the long holding times on total emissions is clearly shown by the large area of the CO and
HCx bars at LSGI. The higher power settings of TO and Climb have a similar influence on the
mass of NO emissions:
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Allison
Carbon monoxide
.~8 G)
- boO
~ s::
....
~~ "CI "CI
s:: -
0.3 ~~ 0
=' =
0
to ..c:
s:: ~ U QJ
0.2 .~ ~ CD ....
'8 0 0 ~
.c '" '"
f:-< 8 QJ f:-<
........ f:-< Q. ~
.c .... Q. QJ Total = 2.93 lb
- 0.1 D ~ - -< p:: D
u
0.0 0 D 0
4.0 2.0 0.5 2.5 4.6 0.2 4.0 2.0
Time in mode-minutes
Unburned hydrocarbons
s:: ::lo
'8 0" Total = 1. 11 lb
........
:S
c::J D ~ c:::::J
0.0
4.0 2.0 0.5 2.5 4.6 0.2 4.0 2.0
Time in mode-minutes
Nitric oxide
0.4
0.3
s::
S 0.2
........ ~
:S
0.1 0
0.0 D D D' 0
4.0 2.0 0.5 2.5 4.6 0.2 4.0 2.0
Total = 2.22 lb
Time in mode - minutes
7200-25
Figure 4-4. Average LTO emissions.
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.- Allison
LSGI = 69% of all CO mass
LSGI = 880/0 of all HCx mass
TO and Climb = 410/0 of all NO mass
Importance of Tr:>.nsierlts
Emissions during acceleration, deceleration, and starting transients were measured. Each
recorded transient was integrated to find an average concentration level from which the mass
values were computed. Table 4-IX contains a comparison of the mass values obtained from
transient measurements and those of the total LTO. From this, it is obvious that transients
represent only a very insignificant portion of the total mass emissions except during engine
starts.
Table 4-IX.
Mass emissions during transients.
(T56-A-15 Engine 108518)
% of total L TO
Running transients Pollutant lb Itransient emissions
Low speed ground idle CO O. 19 6.6
to ground idle HCx O. 058 5.2
Flight idle to takeoff CO 0.56 1.6
HCx No change
NO 0.137 6.2
Takeoff to flight idle CO O. 068 2.4
HCx No change
NO 0.095 4.3
Starting transients
Ambient CO 0.91 31
HCx 0.45 41
NO O. 036 1.6
Hot start No.1 CO 0.86 30
HCx 0.28 25
NO O. 036 1.5
Hot start No.2 CO 0.95 33
HCx 0.51 47
NO 0.048 2.2
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----- ~
v. CONCLUSIONS AND RECOMMENDATIONS
Emissions were measured satisfactorily on the eleven production engines; the average emis-
sion levels and variatkns were determined over the operating range of each. However, the
variations could not be specifically proportioned among true engine variation, instrument
variability, and variation incurred by measuring a production test cycle and converting to the
emission cycle. True engine variability and instrument variability should be assessed by a
test which includes a larger number of engines (samples) and by a statistically planned evalua-
tion of instrument error.
Emissions during engine transients were found to be very low-about one twentieth of the total
LTO mass emissions.
Unburned hydroca.rbons and carbon monoxide transient emissions during engine start (measured
on one engine) were high. They amounted to nearly one third of the HCx and CO mass emitted
during the LTO cycle. Additional testing to verify these values over a larger sample of en-
gines is recommended.
In general, all measurements taken were satisfactory except the lowest levels of hydrocarbons
and oxides of nitrogen where test stand background (HCx) and instrument noise (NO) detracted
from the quality of the measurements. The development of measurement technology should be
emphasized until very low concentration measurements can be made accurately and routinely.
Operation of the chemiluminescent NO- N02 instrument was excellent. Instrument response to
engine transients was much better than that of a long-path infrared instrument. Continued ap-
plication of the instrument in gas turbine emission measurements is recommended.
The theory behind the special 28-hole gas sampling probe used for these tests was proved.
This probe obtained a representative sample of the engine exhaust gases. -
The landing-takeoff (LTO) emission test cycle used for the analysis was developed from a study
of Model T56 engine-powered aircraft. It showed that LTO total mass emissions were highly
sensitive to the length of time the aircr,aft was held stationary during ground operations. Be-
cause of the degree of its influence on total mass emissions, aircraft handling and all of its
variabilities should be divorced from engine emission test cycles.
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-
VI. REFERENCES
1.
Procedure for the Continuous Sampling and Measurement of Gaseous Emissions from Air-
craft Turbine Engines. Society of Automotive Engineers, Aeronautical Recommended
Practice ARP1256 (Final Draft). 25 May 1971.
2.
Aircraft Gas Turbine Engine Exhaust Smoke Measurement. Society of Automotive En-
gineers, Aeronautical Recommended Practice ARP1179. 4 May 1970.
3.
1963 Source Testing Manual. Los Angeles County Air Pollution Control District.
4.
1969 CRC Aviation Emission-Measurement Technique Evaluation.
Council Inc. Report No. 430.
Coordination Research
5.
E froym son, M. S. "Multiple Regression Analysis," in Mathematical Methods for Digital
Computers, Anthony Ralston and Herbert S. Wilf. ed. (John Wiley and Sons, 1960) Sec-
tion 17.
6.
Bastianelli, D. Typical Dynamometer Performance Characteristics of Series ill T56
Production Power Sections from February 1967 to December 1969. Detroit Diesel Allison
Technical Data Report TDR AR. 0031-159. 20 July 1970.
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.Allison
APPENDIX A
Description of Measurement Methods
HYDROCARBON ANALYZER
The Flame Ionization Detector (FID) is an on-line, portable unit containing a Beckman GC-4
burner and a Kiethly electrometer. The FID can be used for altitude engine testing and high-
pressure rig applications. It incorporates a remotely operated burner detector and high-
temperature valving which ensures accurate flow control. The Fill operates on the principle
of hydrogen flame ionization of carbon atoms. This unit was built from designs originating at
the U. S. Bureau of Mines, American Oil Research, and Detroit Diesel Allison. It was placed
in service at Detroit Diesel Allison in December 1970.
Specifications
Sensitivity
Approximately 1 ppm at a concentration of 100 ppm and attenuation
of 10, OOOX. Response is essentially linear.
Range
Parts per billion to 100% concentration.
Attenuation
1,2,4,8,16,32,64,128 on electrometer; steps of lOX on preamp.
Stability
Stabilized electronics are drift free.
Reproducibility
:i:l. 0% with successive identical samples.
Readout
L& N Speedomax recorder. 2 in. I min.
Sample Requirements
o to 0.5 ft3/min exhaust bypass rate. 1 to 10 cclmin sample flow
rate to burner, 5 in. Hg vacuum in burner vessel induces sample
flow of approximately 10 cc/min.
INFRARED GAS ANALYZERS
The Model 200 Luft-type infrared analyzer (LIRA), manufactured by Mine Safety Appliances
Company. was used to measure CO, C02' and NO. Four instruments were assembled into a
cart which contained flow regulators, flow meters, pressure and temperature gages, and other
equipment necessary to measure and maintain sample and calibrating gas flows to each in-
strument.
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Allison
instrument Ranges
CO 0-100,
C02 0-1.5,
NO 0- 300,
0-1000 ppm
0-15%
0-1000, 0-3000 ppm
Accuracy
Rated at 1 % of scale.
NO-NOx ANALYZER
The Thermo Electron (TECO) Model lOA chemiluminescent analyzer was used to measure NO
and NOx in the gas turbine exhaust. The chemiluminescent reaction of NO and ozone is the
basis of operation of the TECO instrument.
Specifica tions
Sensitivity
2.5, 10, 25, 100, 250, 1000, 2500, and 10,000 ppm full scale.
Selectivity
Selective detection of NO with negligible interference from water vapor or
other constituents in typical emission samples.
Re sponse
Less than one second with continuous monitoring; also linear response on all
ranges and from range to range.
Stability
Excellent.
SMOKE
A Bacharach smokemeter, Model RDC, was modified to comply with the SAE ARP1l79 sampling
technique. This is a spot filtration sampling method with a controlled sampling volume and
uses a photometer to grade the stained disks. Filter material is Whatman No.4.
ALDEHYDES
The MBTH method was employed to identify aldehydes. Gas samples are collected in evacuated
bottles through a heated sample line. The bottles contain a dilute solution of 3-nwthyl-2-benzo-
theazolone hydrazone hydrochloride-hence MBTH. A wet chemical analysis follows. This
method covers a range from 0 to 200 ppm.
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Allison
SALTZMAN
The modified Saltzman technique wet-chemical procedure was developed originally as a colori-
metric microdeterminadon of the concentrations of nitrogen dioxide (N02) in the atmosphere.
It has been adapted to exhaust gas measurements by allowing the complete oxidation of nitric
oxide (NO) to N02 prior to analysis. The standard Saltzman reagent is used, and results are
analyzed on a Beckman Model B spectrophotometer.
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Allison
APPENDIX B
Emissions Data Tables.
PTS INITIAL RUN SET POINT DEFINITION
Set points
Engine powe r
1, 17
2, 18
3
4
5
Low speed ground idle
Ground idle
75% normal
100% normal
Military
Takeoff
Decel
6, 10, 14
7, 11
8, 12
9, 13
15
Flight idle
Accel
Reverse
16, 19
Shutdown
PTS FINAL RUN SET POINT DEFINITION
Set points
Engine powe r
1, 14
2
3
4
Low speed ground idle
75% normal
100% normal
Milita ry
Takeoff
Reverse
5, 9
6
7, 11
8, 13
10
Flight idle
Accel
Decel
12, 16
15
Shutdown
Ground idle
-------
Engine Set Speed Fuel Torque Turbine Compr ReI LIRA LIRA LIRA FID Smoke Barom CHO Saltz C1 C1
(rpm) flow (in.-1b) inlet inlet humid. CO C02 NO HCx NO press. (ppm (ppm N02 NO + N02
(lb/hr) temp temp (%) (ppm (% vol) 100 (ppm (ppm (in.Hg) vol) vol) (ppm (ppm
(OF) (OF) vol) vol) vol) vol) vol)
108518-1 2 13500 731 1100 1065 87 50 59 155 40 3 52 28.7
3 13800 1589 12200 1610 90 45 34 343 68 3 54 28.9
4 13800 1980 16800 1850 91 44 34 432 114 15 55 28.9
5 13800 2118 18200 1920 91 44 36 453 14 29.0
10 13800 2260 19500 1970 91 44 50 470 118 10 29.0
12 13400 890 3600 1165 86 52 54 218 40 10 54 28.9
6 13800 2241 19400 1970 91 44 39 470 114 15 56 29.0
8 13400 889 3600 1165 87 50 54 215 38 10 28.9
4 13800 2258 19400 1970 90 45 39 470 112 5 29.0
17 52 355 270 30 390 42
18 13500 742 1100 1050 83 58 155 14 3 28.8
108512-1 2 13500 714 1100 1040 90 49 66 135 37 3 28.6
3 13800 1530 11600 1610 98 38 34 303 91 3 54 28.9
4 13800 1900 16000 1850 100 35 32 368 138 3 29.0
18 13500 712 1100 1080 97 39 155 18 3 28.9
10 13800 2110 18200 1970 102 34 41 435 106 3 29.0
12 13400 881 3800 1205 97 39 57 200 32 3 55 28.9
6 13800 2110 18200 1970 102 34 39 415 130 3 29.0
8 13400 872 3700 1205 97 39 55 200 42 3 28.9
14 13800 2110 18200 1970 102 34 39 435 88 3 57 29.0
17 10000 554 600 1200 98 38 380 265 18 331 28.9 ~
108513-1 2 13500 708 1000 1070 96 44 55 159 21 3 52 28.8 34
tJj 3 13800 1490 11000 1610 100 39 40 309 66 3 53 28.7 89
I 4 13800 1862 15400 1850 102 37 35 405 89 3 56 28.7 126
C'-' 5 13800 1977 16700 1970 102 37 36 426 132 22 55 28.7 ~
10 '3800 2074 17600 1970 102 37 40 441 139 10 55 28.7 g
12 13400 896 3900 1230 99 40 51 208 31 18 56 28.8
6 13800 2072 17600 1970 103 36 39 444 123 19 28.7 139
8 13400 902 3900 1235 99 40 51 208 37 12 28.7 51
17 10000 564 400 1210 97 43 375 277 23 350 28.7 35
18 13500 711 1000 1070 97 43 30 160 28 3 28.5
108517-1 2 13500 726 1100 1070 86 48 54 140 24 3 51 28.9 1 20 26
3 13800 1570 11~00 1610 94 37 34 298 68 3 58 29.0 1 68 73
4 13800 1950 16200 1850 96 34 32 423 107 3 56 29.0 1 100 107
5 13800 2065 17400 1920 98 32 30 479 114 3 29.0 107 114
10 13800 2150 18400 1970 99 30 32 498 107 3 29.0 1 115 120
12 13400 892 3800 1200 94 37 46 235 32 3 28.9 1 31 38
0 13800 2150 18400 1970 99 30 30 493 111 3 56 29.0 107 115
8 13400 896 3900 1200 94 37 46 230 34 3 54 28.9 33 38
14 13800 2150 18400 1970 99 30 29 490 102 3 29.0 1 III 118
17 10000 586 1140 94 37 320 318 20 350 28.9 3 17 25
18 13500 1100 1075 94 37 188 38 3 28.9 22 28
108508-F 1 13500 732 1200 1075 79 43 55 135 29 56 28.8
2 13800 1572 12200 1610 80 42 32 312 94 60 29.0
3 13800 1980 17600 1850 86 35 34 366 126 10 60 29.0
5 13800 2190 19400 1970 88 32 35 419 160 10 58 29.0
6 14300 1080 5100 1375 115 15 35 250 76 30 59 28.9
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Engine Set Speed Fuel Torque Turbine Compr Re1 LIRA LIRA LIRA FID Smoke Barom CRO Saltz CI CI
(rpm) flow (1n.-1b) inlet inlet humid. CO C02 NO RCx NO press. (ppm (ppm N02 NO + N02
(lb/hr) temp temp (%) (ppm (% vo1)100 (ppm (ppm (in.Rg) vol) vol) (ppm (ppm
(OF) (OF) vol) vol) vol) vol) vol)
108507-F 1 13500 720 1100 1075 82 38 60 214 32 45 52 28.7
2 13800 1550 11600 1610 89 30 34 336 82 3 56 28.9
3 13800 1950 16400 1850 91 28 36 427 120 3 57 28.9
4 13800 2080 17700 1920 93 27 37 427 108 3 58 28.9
5 13800 2170 18800 1970 94 26 40 449 132 3 55 28.9
7 13400 910 3900 1225 91 28 54 214 51 3 28.9
9 13800 2170 18800 1970 94 26 42 461 150 28.9
11 13400 908 3900 1220 91 28 54 28.9
14 10000 576 600 1205 89 30 390 283 32 400 43 28.9
15 13500 720 1100 1090 89 30 67 175 34 3 28.7
108506-F 1 13500 721 1100 1090 90 30 142 32 40 62 28.8
2 13800 1522 10700 1610 92 29 30 323 97 13 59 28.9
3 13800 1925 16400 1850 93 28 32 410 129 2 60 28.9
5 13800 2152 19000 1970 93 28 34 443 152 2 60 28.9
6 14200 1058 4800 1385 127 10 35 129 3 57 28.8
7 13400 900 3900 1175 95 26 71 3 62 28.9
15 13500 730 1200 1085 88 32 50 30 23 28.7
108509-F 1 13500 718 1100 990 90 29 52 170 46 32 52 28.7
2 13800 1544 11600 1610 92 28 37 346 102 5 53 28.8
3 13800 1940 16400 1850 93 27 37 442 142 3 53 28.8 ~
4 13800 2045 17600 1920 93 27 35 455 145 28.9
5 13800 2128 19800 1970 94 26 35 470 150 3 53 28.9
OJ 7 13400 908 3900 1250 95 26 37 218 32 8 54 28.8
, 9 13800 2150 18800 1970 95 25 35 490 150 3 28.9 ..'
c...J 14 10000 572 600 1205 91 29 450 29 380 41 28.8 ~
1085i6-1 2 13400 714 10 1070 82 47 63 151 24 7 50 28.8 8
3 13800 1575 119 1610 77 56 34 330 88 3 56 29.0
4 13800 1970 168 1850 80 50 36 410 115 3 58 29.0
18 13500 753 12 1075 78 54 151 24 28.9
10 13800 2190 197 1970 81 49 43 440 164 3 29.1
12 13400 896 38 1195 79 52 58 210 42 3 29.0
6 13800 2175 192 1970 81 49 40 440 138 3 56 29.1
8 13400 900 38 1195 78 54 57 205 28 3 54 29.0
17 10000 54 375 250 6 370 42
108510-F 1 13500 720 1100 1055 76 60 49 163 31 53 28.6
2 13800 1570 12400 1610 80. 55 34 352 74 57 28.8
3 13800 2000 17400 1850 83 49 35 445 102 60 28.8
5 13800 2210 19800 1970 85 46 38 438 100 58 28.9
6 14300 1041 4900 1365 112 20 33 313 82 58 28.8
7 13400 899 4100 1210 84 46 52 222 31 57 28.8
108469-F 1 13500 732 1200 1105 89 34 55 155 15 50 28.8
2 13800 1512 11400 1610 91 32 32 328 108 9 52 28.9
3 13800 1925 16100 1850 92 31 34 410 129 3 54 29.0
4 13800 2020 17100 1920 93 30 32 465 129 29.0
5 13800 2090 17900 1970 94 29 35 471 153 4 54 29.0
6 14300 1040 4300 1410 130 10 35 77 3 53 28.9
7 13400 918 4000 1255 94 29 49 213 42 52 28.9
9 13800 2100 17900 1970 93 30 38 442 29.0
I a initial run set points
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APPENDIX C
Computation Methods from ARP1256
The following computations of mass concentrations from volume concentration and dry to wet
conversions are outlined in the preliminary draft of SAE ARP1256, Procedure for the Continu-
ous Sampling and Measurement of Gaseous Emissions from Aircraft Turbine Engines (May 25,
1971) .
DEFINITION OF TERMS
CO = concentration of CO in exhaust, ppm
C02 = concentration of C02 in exhaust, 0/0
C = concentration of hydrocarbon (HC) in exhaust,
NO = concentration of NO in exhaust, ppm
N02 = concentration of N02 in exhaust, ppm
F = mass rate of fuel usage, lb/hr
wx = mass emission rate of component X,
Wx = mass emission rate of component X,
MC = atomic weight of carbon
MH = atomic weight of hydrogen
CI = (atomic) hydrogen/carbon ratio of fuel
CI = 2 in approximation equations
ppm C
lb /hr
lb /1 000 lb fuel
EQUATIONS FOR CALCULATING WEIGHT OF EMISSIONS
These equations use fuel consumption data and emission concentration values based on wet (or
actual) exhaust measurement. Note that for all this computation, the concentration values for
all species must be on the same basis-that is, either all on an actual or all on a dry basis.
WCO =
CO
MCO -"4 F
(C~ C )~
(Me + CI MH) 104 + C02 + 104
CO
2 - F
104
CO ... C
4+ C02 +-4
10 10
wHC =
..£.F
104
co e
4+ C02 + 7:4
10 10
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Allison
wNO (as N02) =
NO
MN02 _4 F
10
(CO C )
0. MH) 104 + C02 + 104
....
-
NO
3.29 1"04 F
CO C
104 + C02 + 104
(MC +
WCO =
2.801 (CO)
::= 0 20
(CO C ) .
(Mc + a. MH) 104 + C02 + 104
(CO)
CO C
104 + C02 + 104
WHC =
O. 100 (C)
CO C
_4 + C02 + 4
10 10
WNO (as N02) =
(MC +
4.601 (NO)
(CO C )
0. MH) 4 + C02 +-4
10 10
....
-
0.329 (NO)
CO C
_4 + C02 + 4
10 10
CONVERSION OF CONCENTRATIONS (DRY) TO WET BASIS
Concentration (wet basis) = K . concentration (dry basis)
y = water content of intake air (% by volume)
For the case in which all measurements were determined on a dry basis:
Correcting only for water of combustion:
Kd =
100
0. (CO )
100 + -; 104 + C02
Correcting for water of combustion and water vapor in inta~e air:
Kw = Kd
200 - y (1 + -;)
200 - Y + Kd ya (1 - CO)
2 106
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Allison -
APPENDIX D
Airflow at Vario' 'S Values of Compressor Inlet Pressure and Temperature
Pressure Temperature (OF)
(in. Hg) 20 30 40 50 60 70 80 90 100
28.5 34.33 33.69 33.00 32.31 31. 63 30.93 30.22 29. 52 28.81
28.6 34.45 33.80 33. 11 32.43 31.74 31.04 30.32 29.62 28.91
28.7 34. 57 33. 92 33.23 32. 54 31.85 31. 15 30.43 29.73 29.01
28.8 34.69 34.04 33.34 32.65 31.96 31. 26 30.53 29. 83 29. 11
28.9 34. 81 34. 16 33.46 32.77 32.07 31.37 3 O. 64 29.93 29.21
29.0 34. 93 34.27 33. 58 32.88 32.18 31.47 30.75 30.04 29.31
29.1 35.05 34.39 33.69 32.99 32.29 31. 58 30.85 30. 14 29.41
29.2 35. 17 34. 51 33. 81 33. 10 32. 40 31.69 30.96 30.25 29. 51
29.3 35.29 34.63 33. 92 33.22 32. 51 31.80 31. 06 3 O. 35 29.61
29.4 35.41 34.75 34.04 33.33 32.62 31.91 31. 17 30.45 29.72
29.5 35.53 34.86 34.15 33.44 32.73 32.01 31.27 30. 55 29.82
29.6 35.66 34.98 34.27 33.56 32.85 32. 12 31.38 30.66 29.92
29.7 35.77 35.10 34.38 33.67 32.96 32.23 31.49 30.76 30.02
29.8 35. 89 35. 22 34. 50 33.78 33. 06 32.34 31. 59 30. 86 30.12
29.9 36.04 35.36 34.64 33. 92 33.20 32.47 31.72 30.99 30.24
30.0 36.14 35.46 34.73 34.01 33. 29 32.56 31.81 31.07 3 O. 32
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APPENDIX E
Tables of Analyt~cal Results
Regression coefficients R2
Engine Component Al ~ ~ ~ ~ S(y) N
108506 CO -163.57 0 27413.03 - O. 0879 16161.9 18.33 0.978 7*
HCx -241.88 0 30579.1 -0.09168 16444. 1 25.58 0.959 7*
NOx 86. 108 - O. 1995 21174.8 0 3959.9 5.44 0.993 7
C02 O. 00635 0.00006943 191.159 0 -4.3363 0.00204 0.999998 7*
Smoke 59. 182 0 0 0 689.01 1.61 0.395 7
108509 CO - 674. 1 0.61453 0 -0.12159 35570.6 14.302 0.994 8
HCx -600.19 0.522 0 -0.10304 34180.8 12.453 0.995 8
NOx 24.9739 0 0 0.028306 0 9.851 0.969 8
CO2 O. 13116 - O. 0000777 198.701 0.00001033 -7.8736 0.00235 0.999998 8
Smoke 69.0386 -0.012385 0 0.002025 -1261.7 0.4604 0.993 8
108516 CO 380.12 -0.71809 51044.2 0 18869.5 10.51 0.994 9
HCx -371.91 0 47309. 8 -0.1453 16415. 1 11.54 0.994 9
NOx 836. 82 -0.9137 11760.7 0.20119 7905.29 6.720 0.992 9
C02 0.005525 0.00008229 191.27 0 - 5. 2095 0.00304 0.999995 9
Smoke 54. 883 0 99.764 0 -1333.63 0.8109 0.980 9
108518 CO -204.91 0 30618.7 -0.10388 14000. 9 7.802 0.995 11
HCx -368.56 0 46051.8 -0.1519 15413.4 8.893 0.996 11
NOx -73.497 0.092716. 0 0 0 8. 0847 O. 961 11
C02 0.01949 0.00006518 191.55 0 - 5.2703 0.00194 0.999998 11
Smoke 55.9905. 0 0 0 -1245.21 0.9172 0.954 11
108512 CO -163.57 0 27413.03 - 0.0879 16161.9 18.33 0.978 10
HCx -241.88 0 30579. 1 -0.09168 16444. 1 25. 58 0.959 10
NOx 60.275 0 -8131.6 O. 05349 4819.5 16.85 0.898 10
CO2 0.00635 0.00006943 191.159 0 - 4.3363 0.00204 0.999998 10
Smoke 99.2853 -0.054412 1777.08 0.007229 -1389.50 O. 9276 0.976 10
108513 CO -254.7 0 43154 - 0.15786 1938.6 18.74 0.977 10
HCx -761.98 0.4948 38783. 1 - 0.26266 0 14.67 0.988 10
NOx -102.64 0.11032 0 0 0 11.42 0.942 10
C02 0.07827 0 189.97 0.00002149 -1.4863 0.00179 0.999998 10
Smoke 75.8797 -0.030094 1865.48 0 -1311.26 0.7716 0.970 10
Saltz - 32. 52078 0.0568627 0 0.015793 .. 0 4.5497 0.993 10
108517 CO - 80. 58 0 10516.2 -0.03277 19789.2 24.275 0.937 11
HCx -177.10 0 14821.3 -0.03924 26218.9 36.226 0.916 11
NOx 19.271 0 0 0.02076 0 7. 0974 0.967 11
CO2 0.05841 0 196.03 0 -5.7919 0.00327 0.999994 11
Smoke 56.6963 0 0 0 -1369.55 0.92873 0.961 11
N02 9.49107 0 457.802 O. 022492 0 3.2075 0.995 11
NO + N02 13.348 0 728.952 0.021653 0 3.0354 0.996 11
*Based on Engine 108512 regression (see page 4-7).
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.Allison
Tables of Analytical Results (cant)
Regression coefficients
Engine Component Al A2 ~ ~ ~ S(y) R2 N
108508 CO -163.57 0 27413.03 - O. 0879 16161.9 18.33 0.978 6*
HCx -241.88 0 30579.1 -0.09168 16444.1 25. 58 0.959 6*
NOx -264.3 O. 1888 8794.2 -0.03136 10378.6 0.7390 0.99995 6
C02 0.00635 0.00006943 191. 159 0 -4.3363 0.00204 0.999998 6*
Smoke 59.563. 0 0 0 -924.75 0.87872 0.731 6
108507 CO -1694.9 1.6268 8443.8 - O. 4029 2856.4 5.664 0.998 10
HCx -1794. 1 1. 5428 27165.3 - 0.4439 0 8.978 O. 996 10
NOx 27.149 0 0 0.02357 0 9. 1157 0.959 10
CO2 0.0654 0 196.76 0 -6.944 0.005887 0.99998 10
Smoke 56.4114 0 0 0 - 1232. 1 1. 132 0.935 10
108510 CO -163.57 0 27413.03 -0.0879 16161.9 18.33 0.978 6*
HCx -241.88 0 30579. 1 -0.09168 16444. 1 25.58 0.959 6*
NOx -226.45 O. 1698 7356.4 -0.03863 6702.98 3.224 0.998 6
C02 0.00635 0.00006943 191. 159 0 - 4. 3363 0.00204 0.999998 6*
Smoke 58.799 0 0 0 -1369. 2 1.070 0.829 6
108469 CO -163.57 0 27413.03 -0.0879 16161.9 18.33 0.978 8*
HCx -241.88 0 30579. 1 -0.09168 16444. 1 25.58 0.959 8*
NOx -276. 12 0.3312 -7708.5 -0.01717 0 7.273 0.985 8
C02 O. 00635 0.00006943 191.159 0 - 4.3363 0.00204 0.999998 8*
Smoke 49.091 0 381.078 -0.000834 -426.014 0.5504 O. 918 8
*Based on Engine 108512 regression (see page 4-7).
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