NASA TECHNICAL

MEMORANDUM

COONcsI

X

NASA TM X-2930

*/•>

EFFECT OF INCREASED FUEL TEMPERATURE

ON EMISSIONS OF OXIDES OF NITROGEN

FROM A GAS TURBINE COMBUSTOR

BURNING NATURAL GAS

by Nicholas R. Marchionna

Lewis Research Center

Cleveland, Ohio 44135

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION • WASHINGTON, D. C. • DECEMBER 1973

https://ntrs.nasa.gov/search.jsp?R=19740006540 2020-05-12T14:31:05+00:00Z

1. Report No.

NASA TM X-29302. Government Accession No. 3. Recipient's Catalog No.

4. Title and Subtitle EFFECT OF INCREASED FUEL TEMPERATUREON EMISSIONS OF OXIDES OF NITROGEN FROM A GASTURBINE COMBUSTOR BURNING NATURAL GAS

5. Report DateDecember 1973

6. Performing Organization Code

7. Author(s)

Nicholas R. Marchionna

8. Performing Organization Report No.

E-7618

9. Performing Organization Name and Address

Lewis Research CenterNational Aeronautics and Space AdministrationCleveland, Ohio

10. Work Unit No.

501-2411. Contract or Grant No.

12. Sponsoring Agency Name and Address

National Aeronautics and Space AdministrationWashington, D.C. 20546

13. Type of Report and Period Covered

Technical Memorandum14. Sponsoring Agency Code

15. Supplementary Notes

16. Abstract

An annular gas turbine combustor was tested with heated natural-gas fuel to determine the effectof increasing fuel temperature on the formation of oxides of nitrogen (NO ). Fuel temperaturesranged from ambient to 800 K (980 F). Combustor pressure was 6 atmospheres and the inlet-air temperature ranged from 589 to 894 K (600° to 1150° F). The NO emission index in-creased with fuel temperature at a rate of 4 to 9 percent per 100 K (180° F) increase in fueltemperature, depending on the inlet-air temperature. The rate of increase in NO was lowestat the highest inlet-air temperature tested.

17. Key Words (Suggested by Author(s))

Air pollution; Combustion; Oxides of nitrogen;Heated fuel; Natural-gas combustion; Com-bustors; Jet engine

18. Distribution Statement

Unclassified - unlimited

19. Security Classif. (of this report)

Unclassified20. Security Classif. (of this page)

Unclassified21. No, of

19

22. Price*Domestic, $2.75Foreign, $5.25

* For sale by the National Technical Information Service, Springfield, Virginia 22151

EFFECT OF INCREASED FUEL TEMPERATURE ON EMISSIONS OF OXIDES OF

NITROGEN FROM A GAS TURBINE COMBUSTOR BURNING NATURAL GAS

by Nicholas R. Marchionna

Lewis Research Center

SUMMARY

An annular gas turbine combustor was tested with heated natural-gas fuel to deter-mine the effect of increasing fuel temperature on the formation of oxides of nitrogen(NO ). Fuel temperatures ranged from ambient to 800 K (980° F). Combustor pres-

X , -.sure was 6 atmospheres and the inlet-air temperature ranged from 589 to 894 K (600to 1150° F). The NOY emission index increased with fuel temperature at a rate of 4 to9 percent per 100 K (180 F) increase in fuel temperature, depending on the inlet-airtemperature. The rate of increase in NO was lowest at the highest inlet-air temper-

X

ature tested.

INTRODUCTION

This report presents the results of combustor tests which were conducted withheated natural-gas fuel to determine the magnitude of the effect of increased fuel tem-perature on the formation of oxides of nitrogen (NO ).

X

Natural gas has been proposed as a possible fuel for supersonic flight applications(refs. 1 to 3). The fuel, which has a high heat-sink capacity and a low tendency to fueldecomposition, could be utilized as a heat sink in supersonic flight. Natural gas alsohas an advantage over kerosene fuels in that it produces lower NO emissions (ref. 4).

X

Using fuel as a heat sink will raise the fuel temperature. Fuel temperatures signifi-cantly higher than those currently used could produce higher flame temperatures andsignificantly higher exhaust-gas emissions of NO since the formation of nitric oxide

X

(NO) is sensitive to flame temperature. However, higher fuel temperatures also in-crease the flammability limits of the fuel. Increased flammability may allow the pri-mary zone of the combustor to be designed to burn at lean fuel-air ratios, where theformation of NO is lower than at stoichiometric fuel-air ratios.

X

Tests were conducted on a ram induction combustor over a range of fuel tempera-tures from ambient to 800 K (980° F) to determine the effect of fuel temperature onNO emissions. Combustor pressure was 6 atmospheres. Combustor inlet-air tem-perature ranged from 589 to 894 K (600° to 1150° F) and reference Mach number rangedfrom 0.065 to 0.080. Emissions of NCT , carbon monoxide (CO), unburned hydrocarbons

i X

(H/C), and carbon dioxide (COo) were measured.The units for physical quantities in this report are given in both the International

System of Units (SI) and the U.S. customary system. However, measurements duringthe investigation were made in the U.S. customary system.

FACILITY

Testing was conducted in a closed-duct test facility of the Engine Components Re-search Laboratory of the Lewis Research Center. A schematic of this facility is shownin figure 1. A detailed description of the facility and instrumentation are contained inreference 5. All fluid flow rates and pressures are controlled remotely.

TEST COMBUSTOR

The combustor tested was designed using the r am - induction approach and is des-cribed in reference 6. With this approach, the compressor discharge air is diffusedless than it is in conventional combustors. The relatively high-velocity air is capturedby scoops in the combustor liner and turned into the combustion and mixing zones. Vanesare used in the scoops to reduce pressure loss caused by the high-velocity turns. Thehigh velocity and the steep angle of the entering air jets promote rapid mixing of boththe fuel and air in the combustion zone and the burned gases and air in the dilution zone.The potential result of rapid mixing is a shorter combustor or, alternatively, a betterexit-temperature profile in the same length.

A cross section of the combustor is shown in figure 2. The outer diameter is about1.06 meters (42 in.), and the length from compressor exit to turbine inlet is approxi-mately 0.76 meter (30 in.). A snout on the combustor divides the diffuser into threeconcentric annual passages. The central passage conducts air to the combustor head-plates, and the inner and outer passages supply air to the combustor liners „ There arefive rows of scoops on each of the inner and outer liners to turn the air into the com-bustion and dilution zones.

The snout and the combustor liners are shown in figure 3. Figure 3(a) is a viewlooking upstream into the combustor liner. The scoops in the inner and outer liners

can be seen, as well as the openings in the headplate for the fuel nozzles and swirlers.Figure 3(b) is a view of the snout and the upstream end of the combustor liner. TheV-shaped cutouts in the snout fit around struts in the diffuser. The circular holesthrough the snout walls are for the fuel nozzle struts. Figure 3(c) gives a closer viewof the liner and headplate, showing the liquid fuel nozzles and swirlers in place. Thereare a total of 24 fuel nozzles in the combustor. The fuel nozzles were modified for usewith natural gas.

Figure 4 shows a gas fuel nozzle and its installation. The nozzle has six holes of0.476-centimeter (0.188-in.) diameter at a 13.5° angle from the nozzle centerline.Fuel flow was restricted by the small supply hole through the fuel strut, which wasoriginally designed for liquid fuel.

FUEL SYSTEM

The fuel pumping system was capable of providing only 0.45 kg/sec (1 Ib/sec) ofnatural gas at 800 K (980° F) to the combustor because of the previously described flowrestriction in the fuel strut. The fuel heat exchanger was therefore sized accordingly.

The chemical and physical properties of the natural-gas fuel are presented intable I. The natural-gas composition reported is representative of the natural gas usedduring the test program. The gas composition varies and is dependent upon the season,the demand, and the gas field from which it is obtained.

TEST PROCEDURE

Exhaust Gas Sampling

Concentrations of nitric oxide, total oxides of nitrogen, carbon monoxide, unburnedhydrocarbons, and carbon dioxide were obtained with an on-line system. The sampleswere drawn at the combustor exit from three circumferential locations (120° apart) andat five radial positions, through water-cooled stainless-steel probes. The exit instru-mentation plane is shown in figure 2. The sample probe is pictured in figure 5.

Gas sampling system. - The samples collected by the three sampling probes werecommon manifolded to one sampling line. Approximately 18 meters (60 ft) of 0.95-centimeter (3/8-in.) stainless-steel line was used to transport the sample to the analyti-cal instruments. To prevent condensation of water and to minimize adsorption -desorption effects of hydrocarbon compounds, the line was electrically heated to 420 K(310° F). Sampling line pressure was maintained at 1.7 atmospheres absolute to supply

sufficient pressure to operate the instruments. Sufficient sample was vented at the in-struments to provide a line residence time of about 2 seconds.

The exhaust gas analysis system shown in figure 6 is a packaged unit consisting offour commercially available instruments along with associated peripheral equipmentnecessary for sample conditioning and instrument calibration. In addition to visualreadout, electrical inputs are provided to an IBM 360 computer for on-line analysisand evaluation of the data.

The hydrocarbon content of the exhaust gas was determined by a Beckman Instru-ments Model 402 Hydrocarbon Analyzer. This instrument is of the flame ionizationdetector type.

The concentration of the oxides of nitrogen was determined by a Thermo ElectronCorporation Model 10A Chemiluminescent Analyzer. The instrument includes a thermalconverter to reduce NO0 to NO and was operated at 973 K (1290° F). Both NO and total

£t

NO data were taken. . Both carbon monoxide and carbon dioxide analyzers are of thei±nondispersive infrared (NDIR)-type (Beckman Instruments Model 315B). The COanalyzer has four ranges: 0 to 100 ppm, 0 to 1000 ppm, 0 to 1 percent, and 0 to 10 per-cent. This range of sensitivity is accomplished by using stacked cells of 0.64-centimeter (0.25-in.) and 33-centimeter (13.5-in.) length. The CO« analyzer has tworanges, 0 to 5 percent and 0 to 10 percent, with a sample cell length of 0.32 centimeter(0.125).

Analytical procedure. - All analyzers were checked for zero and span prior to thetest. Solenoid switching within the console allows rapid selection of zero, span, orsample modes. Therefore, it was possible to perform frequent checks to ensure cali-bration accuracy without disrupting testing.

Where appropriate, the measured quantities were corrected for water vapor re-moved. The correction included inlet-air humidity, water injected, and water vaporfrom combustion. The equations used were obtained from reference 7.

The emission levels of all the constituents were converted to an emission index(El) parameter. The El may be computed from the measured quantities as proposed inreference 7 or by an alternate procedure which uses the metered fuel-air ratio whenthis is accurately known. With the latter scheme the El for any constituent X is given by

El = -X L±l [x] x 10'3 (1)x M. f

where

EIX emission index in grams of X per kg of fuel burned

MX molecular weight of X

M average molecular weight of exhaust gas"

f meter ed fuel-air ratio

[x] measured concentration of X in ppm

Both procedures yield identical results when the sample validity is good.

Test Conditions

Tests were conducted at a constant pressure of 6 atmospheres and a constant airflowof 50 kg/sec (110 Ib/sec). Gombustor inlet-air temperature was varied from 589 to894 K (600° to 1150° F). Nominal reference Mach numbers ranged from 0.065 to 0.080because of the changes in inlet-air temperature.

Fuel flow rates were limited by a flow restriction in the fuel nozzle strut. All testswere conducted at the maximum fuel flow rates attainable. The fuel flow varied withfuel temperature and resulted in a fuel-air ratio of 0.0125+0.0035.

Data were taken at fuel temperatures near 300, 550, and 800 K (80°, 530°, and980° F).

RESULTS AND DISCUSSION

Data taken during the test program are presented in table n. The NC) emissionsX

data were adjusted to zero inlet-air humidity by multiplying the measured values by1 QTJ

e , where H is the absolute humidity (g of water/g of dry air), reference 8. TheNO emissions data were also adjusted to nominal reference Mach numbers by assuming

X

that NOV varies inversely with Mach number, reference 8.X

Effect of Fuel Temperature on Oxides of Nitrogen

The NO emission index increased with increasing fuel temperature, as shown inX

figure 7. The increase in NO_ with fuel temperature is attributed to increased flameX

temperature in the primary combustion zone, which is caused by the increased enthalpyof the fuel. Increasing flame temperature increases the rate of formation of nitric oxide(NO) with time, reference 8:

[NO] = 9.5k2|exp/-75-5kcal/g-moleVi x [O] x IN.! (2)[ \ RTf /J L *•>

where

[NO] rate of formation of NO, d[NO]/dt

k2 (13±4)xl012 cm3mole~1sec~1

R 1.987 cal/(g-mole)(K)

[NO] concentration of NO

[o] concentration of O

concentration of N,N '2flame temperature, K

If the concentrations of N2 and O remain constant, the rate equation (2) implies an ex-ponential increase in NO formation with increasing flame temperature. The data aretherefore plotted on semilog coordinates and the best straight line is drawn through thedata. Variations from the constant exponential increase in NO with fuel temperature

A.

are attributed primarily to repeatability of the data.The rate of increase in NO which might be expected from an increase in fuel tern-

X

perature can be calculated based on a simplified combustion model. The model specifiesthat all the NO is formed in a primary combustion zone where the fuel-air ratio is

X

stoichiometric and that all the additional enthalpy of the fuel raises only the primary-zone flame temperature, affecting the rate of formation of NO (eq. (2)). The changein flame temperature may be calculated from the change in enthalpy of the heated fuel:

*Hfuel—

with

change in flame temperature

AH change in enthalpy of the fuel due to heating

C_ specific heat at constant pressure of the combustion gases at a stoichiometricfuel-air ratio (ref. 9)

f/a stoichiometric fuel-air ratio

The specific heat C of the combustion gases increases with increasing flame tem7

perature and increasing fuel-air ratio. The stoichiometric flame temperature increaseswith increasing inlet-air temperature.

By using equations (2) and (3), the increase in formation rate of NO concentrationmay be calculated:

exp[NO] _ [R(T0 + AT)j

£ZLi\V R T o /

where [NO]Q corresponds to the rate of formation of [NO] at ambient fuel temperaturefor a stoichiometric flame temperature T .

This calculation was carried out for the minimum and maximum inlet-air temper-atures tested. Figure 8 shows the theoretical results and the actual data resultsnormalized to the value with ambient fuel temperature, 300 K (80° F). At the highinlet-air temperatures the data agree very well with the model. The NO emission indexincreased approximately 4 percent per 100 K (180° F) increase in fuel temperature. Atthe lowest inlet-air temperature, the increase in NO was higher than predicted by the

Ji

model and was approximately equal to a 9 percent increase in NO_. per 100 kelvino(180 F) increase in fuel temperature. The model does predict a greater increase in

NOX due to fuel heating at lower inlet-air temperatures, partially because of the dif-ference in specific heat and partially because of the steeper gradient of the exponentialfunction at the lower flame temperature.

One factor which the model does not take into account is the increased flammabilitylimits of the fuel when it is heated. Increased flammability allows the fuel to burn overa wider range of fuel-air ratios, where the rate of formation of NOV is lower than at the

X

stoichiometric fuel-air ratio. The combustor would have to be redesigned to take ad-vantage of this possibility.

Effect of Fuel-Air Ratio on Oxides of Nitrogen

The data shown in figure 7 were taken at varying fuel-air ratios. There was nosignificant difference in NOY emission index with varying fuel-air, ratio between these

X

data and data from the same combustor burning ASTM Jet-A fuel (ref. 10). However,data at constant fuel-air ratio with natural gas have not been taken. If the NO..

X

emission index increases with increasing fuel-air ratio, the increase in NO with fuelX

temperature would probably be larger than that shown in figures 7 and 8.

Combustion Efficiency

Combustion efficiency was over 99.6 percent at all the test conditions. The effi-

ciency data determined from gas sample measurements are shown in table n. Com-bustion efficiency was lowest at the lowest inlet-air temperature and increased with in-creasing inlet-air temperature.

Effect of Inlet-Air Temperature on Emissions of Oxides of Nitrogen

Figure 9 shows the effect of inlet-air temperature on NO emissions when naturalgas was used at ambient temperatures. The data have been adjusted to a constant ref-erence Mach number of 0.065 for comparison with liquid ASTM Jet-A fuel from refer-ence 8 for the same combustor. The use of natural gas gave less NO emissions than

•*»

the use of liquid fuel, as has been experienced by others (ref. 4). Also the effect ofinlet-air temperature on NO emission index appears to be slightly larger when using

A. ' • •

natural gas, tending to bring the curves together at high inlet-air temperatures. Thisimplies that the NOX emissions may be the same with both fuels if the reactant temper-atures are very high.

Sample Validity

A calculation of the gas sample fuel-air ratio was made for each data point. Theratio of the gas sample fuel-air ratio to the metered fuel-air ratio (fuel-air-ratio ratio)is presented in table n. The maximum data scatter is ±4.5 percent about a mean of1.105. The fact that the mean value is 10.5 percent high is probably symptomatic of thelocation of the sampling probes and is not expected to influence the trends in the data.

SUMMARY OF RESULTS

Tests were conducted to determine the effect of increasing fuel temperature on theformation of oxides of nitrogen (NO ). An annular gas turbine combustor was tested

H

with natural-gas fuel at fuel temperatures from ambient to 800 K (980 F). Combustorpressure was 6 atmospheres and the inlet-air temperature ranged from 589 to 894 K(600° to 1150° F). The following results were obtained:

1. The NO increased with increasing fuel temperature. The rates of increase inx • ^.NO were between 4 and 9 percent per 100 K (180 F) increase in fuel temperature de-

X

pending on the inlet-air temperature. The rate of increase in NO was lowest at theJi.

highest inlet-air temperatures tested.

2. With fuels at ambient temperature using natural gas gave less NO emissionsX

than using liquid ASTM Jet-A in the same combustor. With higher inlet-air temperatures the difference between the NO emissions with Jet A fuel and natural gas was

Ji

lessened.

Lewis Research Center,National Aeronautics and Space Administration,

"Cleveland, Ohio, October 1, 1973,501-24.

REFERENCES

I.Weber, Richard J.; Dugan, James F., Jr.; and Luidens, Roger W,.: Methane-Fueled Propulsion Systems. Paper 66-685, AIAA, June 1966.

2. Whitlow, JohnB., Jr.; Eisenberg, Joseph D.; and Shovlin, Michael D.: Potentialof Liquid-Methane Fuel for Mach 3 Commercial Supersonic Transports. NASA TND-3471, 1966.

3. Joslyn, C. L.: The Potential of Methane as a Fuel for Advanced Aircraft. Aviationand Space: Progress and Prospects. ASME, 1968, pp. 351-355.

4. Hilt, M. B.; and Johnson, R. H.: Environmental Performance of Gas Turbines.Rep. 71-GTD-10, General Electric Co., Mar. 31, 1971.

5. Adam, PaulW.; andNorris, James W.: Advanced Jet Engine Combustor TestFacility. NASA TN D-6030, 1970.

6. Rusnak, J. P.; and Shadow en, J. H.: Development of an Advanced Annular Combustor.Rep. PWA-FR-2832 Pratt & Whitney Aircraft, (NASA CR-72453), May 30, 1989.

7. Procedure for the Continuous Sampling and Measurement of Gaseous Emissionsfrom Aircraft Turbine Engines. Aerospace Recommended Practice 1256, SAE,1971.

8. Marchionna, Nicholas R.; Diehl, Larry A.; and Trout, Arthur M.: Effect of InletAir Humidity, Temperature, Pressure, and Reference Mach Number on the Forma-tion of Oxides of Nitrogen in a Gas Turbine Combustor. TN D-7396, 1973.

9. Poferl, David J.; Svehla, Roger A.; and Lewandowski, Kenneth: Thermodynamicand Transport Properties of Air and the Combustion Products of Natural Gas andof ASTM A-1 Fuel with Air. NASA TN D-5452, 1969.

10. Marchionna, Nicholas R.: Effect of Increased Fuel Temperature on Emissions ofOxides of Nitrogen From a Gas Turbine Combustor Burning ASTM Jet-A Fuel.NASA TM X-2931, 1973.

TABLE I. - PHYSICAL PROPERTIES OF NATURAL GAS

Densitya, kg/m3 (lb/ft3)Net heat of combustion (calculated), J/kg(Btu/lb)Normalized chromatographic analysis (calculated), vol.

MethaneEthanePropaneHydrocarbons (C,, C^, Cg)NitrogenCarbon dioxideOxygen

0.7320 (0.0457)4.977xl07 (2.140xl04)

93.503.530.530.321.051.07

TraceaDensity in kg/m3 is at 289 K (1.02xl05 N/m2 at 273 K). Density in lb/ft3 is at

60° F (30 in. Hg at 32° F).

10

02 r?c g

ll<UO.

o

11" 0

S "s •»fo*O -rt<

|»g -3K S

gKS

1 „i 20zos ^ s£ S 1 s*oj g S *"3 £K

1 &1 s1 s3 S

•N°2•s 2 SILlrt 2

•3 |

£

>>"3 o §x * •§§ s !>,E•3X

n*a Z

S e*

1 8§1 ota O

W 0

X

Fue

lte

mpera

ture

,K

1

111*~ S i -

O)

of

2 3 3 ££ 2 S «

a

1 8

O

t- fc 10 -fc

O O CO CM US CO

eo CO m C- t- t-

§ -v 10 in o t-O tO CM US CO

CD to us t- D- e-

tn

0 *

o

CM e- os to us to*? ,j. & *f *# Tt-to to co' to to too o o o o oo

C- tD (O t- C- C-

a> at <y> 01 01 01O> O> O> O> O> OJ

« m « Tf 01 QDN c-j M ~4 •& ^H

O O O O) CO OiT-l l-H ^H O O Oo o o o o oo

a> oo m co co ^-to o t- « m (0 tO US C- t C-

CNJeo•* ^

5O

to co eo c- 01 co

in m tn <o co co

co to o -«r 01 ^Hin in m « c-a j-O o o o <-i oeo M co eo PS eo

co CM eg -4* m co

C- 00 O) (D tO to

(M CO COco in m eo ^ -vco TT <£> en OJ a.

^ ^ ^

CN eo eo -*t< ift to5m eo o o o

m tn CD oo oo

co r- eo co us in

(O O> CJ O O O~* i-l CN r* r-t i-«

CD tO CD CD CO CO

e» co m co eo CMC— Tf ^H c£3 CO CO

0 -1 -i O 0 0us in tn us in us

i ^< ^ us us »n

ci 01 eo c- o> oO o «-< c^ w eo

* CO CJ OO O> OiCO CO OJ * <O C-

Oi Oi O *-• « --1

<M

o m

eo c^ CM ^H CD vCM CM OJ CM --. Hr- r- c- c- c- c-o o o o o o

OJ Oi Oi Oi Oi Oi

o eft at a as oC71 Oi OS Oi Ol OJ

*r eo CD eo c- oo-H — 1 CO Ol O «-l

.-» « O O> O> O)^H -H ^H O O Oo o o o o o

o in as f- m to

O O CO US CO O>

ci 01 01 o o o

oo Tf co m CM «eo eo as co CM mO O O O> O Oco co eo 04 co co

m CM o •— CN co

co eo co •* ^ eo

CM SM CM OO TT •*o o o o o o

eo eo co O O Oitn us us oo oo c~

eo •<»• us 0 — oUS US US CO CO CO

M O l-l « « -1

„ ^H « — > M W

CO CO CD CO CO CO

C- O eo "T i-< O1-1 os a> -H •-" "•»O OS OS O O O»n " •v us us us

co co co o> os a>

t- CO CO CM eo CD

00 t- CO CO CO CO

O O co O O O

US TJ" US CO CO CO

CD t- 00 CD i— t-US CM -T OS O> OS

0 0 0 0 0 O

01 OJ 0> OS OS OS

s s s s s s

•W CM 00 -<T t- CM^H 01 eo o O CM-i 0 i-( ^ i-» —

§ O) Cft O O O

0 0 0 0 0

0 t- 0 •V — 0>

- -

OO US rH CM CO US

" " U5 N CM CM

- us co co i— eoTt- CO O r-l CM CO

eo CM co eo eo co

CM CO CO CM CM CM

eo ^* coo *• o o

•<!• eo CM m CM t-O O O CO CO CMco oo co in us us

-H CM tj- as os o•* TT •* CO CO V

TT C- O) -H O CM

CO CO CO CO CO CO

co m us i— o usCO I-H -V .— t- «

os as 01 CM ^H w•cr ^ •fl1 us m us

M co us m r- oo

CM CM S N N W

us o d us o o•w us c- as M M

CD eo cp OS O O

90

D~ CO CP CM (O COco c- t- o o asc- c- t- co oo c-0 0 C» 0 0 0

OS OS dS OS OS OS

as os cP os os oso» os os os os as

o o us co co mCO OO OS O OS O0 0 C? -< 0 —

_ ^ i as as os1-1 rt i O O Oo o o o o o

o cJ CM -<r co

r eo oP eo eo co

us us ir> co oo oo

OS OS ^* CO C- O• Tf O> CM O5 CMos as o* o os oCM M CM CO CM CO

CM W CM

o o oo o o

as o O "»• co eoCM CO CO OS O ^nm us u? c~ co oo

t- OS O CM CM CMas os o o o o

-

co CD tp eo co co

S OS U5 OS N eD• US i-> CM 0

O OS O5 O O OITS -<r •«• us tn tn

i s s; s

.-1 US CM — .

10 2 ^ N

co eo O co^- CO" C- CO

US OS C4 CO

US CM CO O

o o o o

us m c^ co•* »-. U) COto c- r- t-o o o o

co as os os

S os as osos as as

CO US O CMO co r- coi-< O O O

o o o o

CM O CO CO

- -

CO CO O C~CM co -<r eoTT us co r-

o o o o

S CO t~C- CD OS

TT CO ^- -fl*

^H V CD CO^-. eo os c-CM CM CM CM

US -i

5o o o

O OS O COOS O CJ •—CM co eo eo

M -H CO C-Cft CO ^ CJS

0 eo •* CM

CO CD CO CO

OS - CO -Wr- t- eg oo

m •<*• •* TJ-

11

Fuel available:300 K (80° F);

20 to 240 N/cm(0 to 350 psia)

_L' Fuel measuring

Combustion289 to 311 Kup to 136 kg/up to 114 N/c

air available:160° to 100° F);sec (300 Ib/sec);m^ (165 psia)

A

^ Air heatexchanger

ir measorifi

1

1

uring

" ?— >ki — -Inlet flow

iorifice

r

Fuel heatexchanger

i r

Test sectionQ Altitude or

f^xTl ^- atmosphericr u . . , exhaustExhaust control

Figure 1. - Test facility.

Inlet measuringstation

Referencearea plane

77.72(30.60)diam

Exhaust-gasmeasuringstation

Figure 2. - Cross section of combustor. Dimensions are in cm (in.).

i06.2(41 80)diam

54.35(21.40)diam

CD-11423-28

12

Scoops - • Combustorouter liner

(a) View from downstream end.

SnoutAir passages

Inner

Center

Outer

Outer /shroud

C-70-1830

/-Inner Cutouts in snout/ shroud for diffuser struts

- Cuiouts for fuelnozzle struts

0.305 mi l f t )

(b) View from upstream end.

Figure 3. - Annular ram-induction combustor.

13

C-69-3937

I Fuel: nozzle

~

^ £ /--— •Jfcfc

Cooling slots-/ \~Scoops

(c) Closeup view from downstream end.

Figures -Concluded.

C-67-360?

Fuel nozzle

Holediam, 0.476cm (0.188 in.)six holes on 1.27-cm (0.50-indiam circle-i

Figure 4. - Natural gas fuel nozzle.

14

Coolingwater in

"-Water-cooledjacket

Gas sample

Coolingwater out

C-72-2826

Figure 5. - Gas sampling probe.

15

(a) Gas sampling instrument console.

Two five-poi ntwater-cooledsampling probe

Heated |line

Bypassvent

Control-room-typewriter

1On-linecomputer 1

Dual-channelrecorder

Indicatingmeter

Controlvalve

inletpressuregage

Inletthermocouple

(b) Schematic diagram of gas analysis system.

Figure 6. - Exhaust-gas analysis system.

16

30

"o>

I 20&TVJo•z.•sen

| 10c oo 8

Nominalinlet-air

temperature,K

> 589i 755> 838> 894

Nominalreference

Machnumber0.065

.072

.078

200 300 400 700 800 900500 600Fuel temperature, K

Figure 7. - Effect of fuel temperature on NOX emission index. Pressure, 6 atmos-pheres (corrected to zero humidity).

17

1.5

1.4

~x1.3o

1.2

1.1

1.0

Inlet-airtemperature,

K

300 400 500 600 700 800Fuel temperature, K

Figure 8. - Effect of fuel temperature on nor-malized NOX emissions - compared to resultsof theoretical model. (Data points omittedfor clarity of presentation.)

30

"533

? 20

^TVJ

*oC7>

I 10

Jet Alref. 8)

Natural gas

500 600 700 800 900In let-air temperature, K

Figure 9. - Effect of inlet-air temperature on NOXemission index for natural gas and Jet A fuel. Pres-sure, 6 atmospheres; reference Mach number, 0.065;zero inlet-air humidity; ambient fuel temperature;nominal fuel-air ratio, 0.0155.

18 NASA-Langley, 1973 33 E-7618

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

WASHINGTON. D.C. 2O546

OFFICIAL BUSINESSSPECIAL FOURTH-CLASS RATE

BOOK

POSTAGE AND FEES PAID

NATIONAL AERONAUTICS ANDSPACE ADMINISTRATION

451

POSTMASTER : If Undeliverable (Section 158Postal Manual) Do Not Return

"The aeronautical and space activities of the United States shall beconducted so as to contribute . . . to the expansion of human knowl-edge of phenomena in the atmosphere and space. The Administrationshall provide for the widest practicable and appropriate disseminationof information concerning its activities and the results thereof,"

—NATIONAL AERONAUTICS AND SPACE ACT OF 1958

NASA SCIENTIFIC AND TECHNICAL PUBLICATIONSTECHNICAL REPORTS: Scientific andtechnical information considered important,complete, and a lasting contribution to existingknowledge.

TECHNICAL NOTES: Information less broadin scope but nevertheless of importance as acontribution to existing knowledge.

TECHNICAL MEMORANDUMS:Information receiving limited distributionbecause of preliminary data, security classifica-tion, or other reasons. Also includes conferenceproceedings with either limited or unlimiteddistribution.

CONTRACTOR REPORTS: Scientific andtechnical information generated under a NASAcontract or grant and considered an importantcontribution to existing knowledge.

TECHNICAL TRANSLATIONS: Informationpublished in a foreign language consideredto merit NASA distribution in English.

SPECIAL PUBLICATIONS: Informationderived from or of value to NASA activities.Publications include final reports of majorprojects, monographs, data compilations,handbooks, sourcebooks, and specialbibliographies.

TECHNOLOGY UTILIZATIONPUBLICATIONS: Information on technologyused by NASA that may be of particularinterest in commercial and other non-aerospaceapplications. Publications include Tech Briefs,Technology Utilization Reports andTechnology Surveys.

Defai/s on the availability of fhese publications may be obtained from:

SCIENTIFIC AND TECHNICAL INFORMATION OFFICE

N A T I O N A L A E R O N A U T I C S A N D S P A C E A D M I N I S T R A T I O NWashington, D.C. 20546