21
0, \ R&T No. E’TT.nn r RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS OF FIVE FUELS IN AN ANNULAR TURBOJET COMBUSTOR By Jerrold D. Wear and Edmund R. Jonash Flight Propulsion Research Laboratory Cleveland, Ohio NATIONAL ADVISORY COMM$&‘@~~Y FOR AERONAUTlCS~\;~i:. -;. WASHINGTON June 7, 1948 (-Jcl 14 kB8 https://ntrs.nasa.gov/search.jsp?R=19930086077 2020-06-18T18:10:20+00:00Z

RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

  • Upload
    others

  • View
    0

  • Download
    0

Embed Size (px)

Citation preview

Page 1: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

0, \ R&T No. E’TT.nn

r

RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS

OF FIVE FUELS IN AN ANNULAR TURBOJET COMBUSTOR

By Jerrold D. Wear and Edmund R. Jonash

Flight Propulsion Research Laboratory Cleveland, Ohio

NATIONAL ADVISORY COMM$&‘@~~Y ’ FOR AERONAUTlCS~\;~i:. -;.

WASHINGTON June 7, 1948 (-Jcl 14 kB8

https://ntrs.nasa.gov/search.jsp?R=19930086077 2020-06-18T18:10:20+00:00Z

Page 2: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

F NACA FM No. E7L30

1

NA!l!IONALADVIXEECO~ FOR LLEzsoNAmcs u- - Memo

COMBUS'IXON-EETICIENCYAISITUDE-IJMIT lXVTSTIG&3!ION8

By Jel~old D. Wear and IEdmund R. Jonaeh

Five fuels of various boiling temperatures and variou~~ hydra- carbon tgpes were inveetigated in a jet-propulsion annular combustor of U&inch diameter to determine the effect of fuel bofling temper- ature andparaffFnic&d aromatic hydrocarbon typea on cormbustion efficiency and altftude operational l&it.

.-

Y

The fuels usea Xn this inveetigation were ccatonercial isoheptane, AN-F-28R, A&F-32, benzene, and aromatic eolvent. Commercial ieo- heptane, AN-F-28R, and. AN-F-32 were con&&red praffinic fuels wfth low, medium, and high bofling temperaturea, respectively. Benzene and aramatic solvent were considered aromatic fuels wfth low and high boiling temperatures, respectfvely.

At the severe inlet-air condition (unstable combustion), the highest combustion efffcienciee were obtained with the parafflnfc and aromatic fuels tith low boiUng temperatures (isoheptane and benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air condition (intermediately stable combustion), the paraffFnic fuels with low and medium boiling temperatures (isoheptane and AN-F-28R) gave the highest combustion efficiencieff, which varied from 70 to 95 percent, The mnrlrmnn variation of alti- tude operational limit among the fuels wa8 5000 feet.

An investigation to determine the effect of fuel boiling tem- perature and hydra-bon tme on combustion efficiency in jet- propulsion engine combustore was conducted at the NACA Cleveland laboratory.

Page 3: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

2 NACA RM No. E7I.30

Investigation of several fuels in tubular combustors (refer- ences 1 and 2) has indicated that at severe operating conditions the combustion efficiency decreases as the boiling temperature of the fuel increases.

Results reported in reference 3 indicate that as the combustor from an engine is operated at increasingly higher altitudes, com- bustion becomes less efficient until the ccmbustor-outlet gas tem- perature is insufficient for engine operation or until combustion ceases.

The investigation reported herein was made to determine the effect of fuel boiling temperature and paraffinic and aromatic type hydrocarbons on combustion efficiencies for a wide range of inlet-air conditions and the'effect on the altitude operational limit of the fuels. The investigations were made on a lOi-inch- diameter annular combustor.

APHRATUS AND INSZWMENTATION

A diagram of the general arrangement ai? the combustor and the auxiliary equipment is shown in figure 1. Air flow to the combus- tor was measured by a square-edge orifice installed according to A.S.M.E. specifications and located upstream of all regulating valves. The combustor-inlet air temperature was regulated by an electrical heater. The ccmbustor-inlet air quantities and pres- sures were regulated by remote-control valves in the laboratory air-supply and e*aust systems.

A diagrammatic cross section of the combustor and the auxiliary ducting, position of instrumentation planes, and location of temperature- and pressure-measuring instruments in the instru- mentation planes is presented in figure 2. The combustor occupies the annular space around the compressor-turbine shaft of a turbojet engine. Observation windows were installed at severetl locations for visual inspection of the combustion. Air is admittcad into the combustion zone by means of en annular basket perforated with longitudinal rows of holes. Thermocouple junctions and total- pressure taps in each instrumentation plane were looated at centers of equal areas. Construction details of the temperature- and pressure-measuring instruments are shown in figure 3.

*

*

Fuel WBB injected into the combustor by 12 centrifugal, hollow- cone fuel nozzle8 with 8G-degree spray angles that were equally

Page 4: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM No. ETWO 3

spaced on a common manifold. Each nozzle has a rated capacity of 6 gallons per hour at a mandfold pressure differential of 100 pounds per square inch. Fuel flows to the combustor were measured by rotameters calibrated for each fuel.

Freesure data were obtained by water and mercury manometers. Thermocouples were connected through multiple switches to two cali- brated, self-balancing potentiometers, one with a -lCO" to 700° F range to record the inlet temperatures (sect~ion A-A, fig. 2) and one with a O" to 24ooO F range to record the outlet tmseratures (section B-B, fig. 2).

The fuels used in thia investigation were commercial isoheptane, AN-F-28R, AN-F-32, benzene, and aromatic solvent. Commercial iso- heptane, AR-F-28R, and AN-F-32 were considered as paraffinic fuels with low, medium, and high boiling t~erxtures, respectively. Benzene and aromatic solvent were considered aromatic fuels with low and high boiling temperatures, respectively. The AN-F-28R and AN-F-32 were considered as psraffinic fuels -inasmuch as data reported in reference 1 show ver ,little difference in the effect on combus- tion efficiency of a inic, olefiric, and naphthenic hydrocarbons.

Laboratory Inspection data of the fuels are listed in the fol- lowing table:

A.S.T.M. distillation Aromatic Hydrogen- Lower Spe- temperature content carbon heating cific

Fuel (91 (volume ratio value Ini- SO-percent Final percent) (Btu/lb) ryv- tial evaporated

Paraffinic Commercial 170 180 206 0 0.177 18,900 0.727

isoheptane AN-F-28R, 114 222 336 15 .176 18,700 .725

batch 2 m-F-32 330 . 370 462 11 .168 18,550 .797

2enzene .kcmatic

solvent

Aromatic 170 172 174 loo 0,088 17,400 0.877 310 328 362 99 .115 17,600 .873

Page 5: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

IUACA RM No. E7l30

Combustion Efficiency

The combustion efficiencies cf the fuels were determined at the three followdng arbitrarily chosen inlet-air condItiona, rep resenting the range encountered with conventional ccqresaor- turbine units; inlet-air conditione 1, 2, and 3 were characterized as severe (unstable combustion), moderate (lnte?mMiately stable combustion), and favorable (stable combustion), respectively:

Inlet-air Inlet-air Inlet-air total condLtion total pressure

(in. ELg absolute) temperature

(W 1 2 30.7 160 3 51.1 250

Specific mass air flowa

(lb/m-sq ft) 2.15, 2.53, 2.91 3.83, 4.50, 5.18 6.01, 7.07, 8.15

%xlet-air flow based on combustor maximum &oss-sectional area of 0.505 sq ft measured 12 in; downstream of sec- tion A-A, (fig. 2).

The fuel-air mixture in the combustor was ignited by an ignition plug (fig. 2); after combustion was started, the ignition plug was deenergized. At any desired set of combustor inlet-air condl.tions, the appropriate Inlet-air temperature, pressure,a+ mass air flow were established at a low fuel flow. From that con- dition, the fuel flow was gradually Increased until local combustor-outlet temperatures (sec. B-B, fig. 2) of apmxImately 18000 F were reached or blow-out occurred. An approate average combustor tempemture rise of 12CO" F was possible tith a limit of 18000 F on local combustor-outlet temperatures. A local ccmbustor- outlet bruperature exceeding 18000 F was considered unsafe for the instrumentation.

Altitude Operational Limit

Combustor-inlet and combustor-outlet conditions used for investigating the altitude operational limits of the fuels wers obtained from the manufacturer's performance estimates of a compressor-turbine unit using an annular ccmbustor. Ateachsdmu- lated rotational speed and altitude condition, the fuel flow was increased from the starting fuel flow in an effort to obtain an average combustor-outlet temperature equal to or greater than that required for engine operation at the same conditions. The highest

P.

Y

Page 6: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM No. E7IZiO 5

simulated altitude at any one simulated rotational speed for which i( the required average combustor-outlet temperature could be obtained

was designated the altitude operational limit of the fuel for this combustoratthe simulatedrotationalspeed.

The performance of the fuels was evaluated by means of data from instruments located at sections A-A and B-B (fig. 2).

The average reading of the two thermocouples located in sec- tion A-A was used as the inlet-air total temperature; the irilet- air total-pressure values were averages of the readings of the six total-pressure tubes located, in section A-A. At section B-B, the average reading of the 36 thermocouples was used as the average ccunbustor-outlet gas total temperature, taking the thermocouple readings as true values ofthetotaltemperature.

Average cambustor temperature rise was taken as the average combustor-outlet total temperature (section B-B) minu the average combustor-inlet total temperature (section A-A). Combustion effi- ciency is arbitrarily defined as the ratio of the theoretical weight of fuel required for the observed average combustor temperature rise to the actual weight of fuel consaed for the observed average ccmbustor temperattie rise. Computations of theoretical fuel-air ratios were made from figure 5 of reference 4.

In order to place the petiormance CXIT the various fuels on a comparable basis, heat input (poduct of fuel-air ratio and lower heating value of the fuel) is used in place of fuel-air ratio on the plots.

RESULTS AND DISCT3SXON

Combustion Efficiency

Lnvestigation of each fuel was repeated at the intermediate air-flow condition of the three inlet-air conditions to determine the reproducibility of the data. The two Fnvestigations with any one fuel were made on different days with intervening investiga- tions . The two sets of data for any one fuel were used for fairing the curve. The repeated investigations are represented by single- tail data points.

Page 7: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

6 mACARMNo.E7L30

-air onditionlr -The variatlonofaverage canbustor temperatutw risZ with heat rzlput is shown in figure 4. Lines of theoretical cmhxstion efficle~y (c~culatedaerpreviouslybefined) are included on this plot and apply to sl.l the fuels. Double-tail data podnts represent data at very unstable cc&bustloPand were not uf3ed to fair the curves.

AU. the fuels at the intemediate andhlgh air-flow conditions and&?-F-282 at the laweclr-fl~c~tianwerel~~dbyblow-aut before an average ccmbustor temperature rise of approximately 1200' F wss obtalued. Caonbuationbecsme erratic as the blow-out limltwss approached. Aromatic solvent was limited by blow-out at all air-flow coxlditiocne. With a3mnatL.c solvent at the low air- flow condition, the mEc&mml averege cmbustor temperature rise obtaked was 250° F (ccsibustion effiuiency of 15 percent), there- fore data for this fuel sre not Included on the plot.

With the exception of lsoheptane at the high sir-flow condo- tion, the combustor temperature rise Increased with bp increase In heat Input to the point of blow-out, end the ccanbustlon efficiency lncreaseduithan lnorease Inheatinputbutreached amaxImam before blowout ocourred.

Exceptatthe high sir-flowconditionl the paraffinic fuelWLtb a high boiltug tauperature (AX-F-32) gave as lsrge a canbustor tern- perature rise (at Lowe efficiency) ss did the peraffdnic fuel (iso- heptsne) end emmatic AEel (benzene) withlowbodU.ng temperatures. The highest cmnbustion efficfencies were obtained with isoheptme end benzene endwere found to vary FKmn 30 to 58 percent, depending on heat input.

Variaticm of combustion efficiency smong the fuels end effect of air flow on combustion efficiency are presented in figure 5. Data me cross plots of fdgure 4 at two vslues of heat input.

TheperaffXnic fuelswIthlowsndmedimbodJJ.ngtemperatures (isoheptarm end AN-F-281R) gave canbustion efficiencies f&m 8 to 20 Percent~aterthantheparaffinicfuslwittrahiShboiling lxaperature (AN-F-32) at two values of heat input.

Co&t&ion efficiencies of the fuels were decreesed 7 to 26 percentwithkcreaseinairflow fortherangeofairflows investigated.

Inlet-air ccmdltion 2. - Cunbustion was stable at this IxiLet conddtim and peek temperatume limited the Investigation in each cage. A plot of averwe cmbustor tesrperature rise with heat input

Page 8: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM No. E7L30

is presented in figure 6. The combustortemperature rise increased steadily with increase in heat input over the range investigated. With the exception of the ature (aromatic eolvmt),

aromatic fuel with a high boil- temper- the combuetfon efficiencies of the fuels

Increase only slightly with increase in heat input above a combustor temperature rise of 8000 F. The paraffinic fuels with low and medium boiling temperatures (isoheptane and AN-F-28R) gave the highest combustion efficiencies, which varied from 70 to 95 percent.

Data sharing the variation of combustion efficiency among the fuels and the effect of air flow on combustion efficfency are pre- sented in fim 7. For two values of heat input, ieoheptane and AN-F-28R gave the highest combustion efficiencies over the ra~lge of air flows investigated.

Increasing the air flow over the range investigated had Little effect on the combustion efficiencies of ieoheptane and AN-F-28 ; an increase in the air flow, however, raised the combustion eff B - ciency of AN-F-32 about 6 percent and decreased the combustion' efficiency of benzene 8 percent and of aromatic solvent 5 percent.

Eata taken at condition 2 with intermediately stable ccmbustfon do not show as much performance difference among the fuels as data taken at condition 1 with unstable combustion.

Lnlet-air condition 3. - Combustion was very stable at this condition and as in condition 2 the inveetigations were lfmited by peak temperatures.

As shown in figure 8, the ccanbuetor temperature rise increased steadily with increase in heat input. The variation of combustion efficiencies among the fuels and effect of air flow on combustion efficiency at two values of heat input are-presented in figure 9. Except for aromatic solvent at the low value of heat input, the variation of the combustion efficienciee among the fuels is small, and heat input had very little effec t on the combustion efficiencies of the fuels. All fuels except the aromatic solvent gave combus- tion efficiencies above 90 percent for the me investigated.

Lncreasin& the air flow over the range investigated had little effect on the combustion efficiencies of any of the fuels except aromatic solvent at low values of beat input where combustion efficiency decreased 15 percent.

Page 9: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

8

Altitude Operational Limit

IIACARMNo.EZ30

Data showing the altitude operational limit of the various fuels at different values of percentage rated simulated engine rota- tional speed are presented in figure 10. Combustion efficiencies of the five fuels at their altitude operational limits are included in the figure.

The spread in altitude operational limit among the f uela for all speeds varied from a-pproximately 2WO to 5000 feet. Although the spread in altitude limit of the fuels was small, AN-F-28R and aromatic solvent generally had the lowest altitude limits. The altitude Limit of isoheptane and AN-F-32 was approximately the same at rated rotational speed, however the combustion efficiency of isoheptane was 16 percent greater than that of m-F-32. The ben- zene permitted the highest altitude limit at rated simulated rota- tional speed.

From combustion-efficiency and altitude-operational-limit investigations of five fuel8 made in a jet-propulsion annular com- bustor of lO$-inch diameteqthe followiq results were obtained; the combustion-efficiency investigation was made at inlet-air con- ditions characterized a8 Bevere, moderate, and faVOrable:

1. At the severe inlet-air condition (unstable combustion), the highest combustion efficiencies were obtained with the paraf- finic and aromatic fuels with low boiling temperaturea (isoheptane and benzene) and were found to vary from 30 to 58 percent.

2. At the moderate inlet-air condition (intermediately stable combu8tion), the paraffinic fuels with low and medium bolting tem- peratures (ieoheptane and AN-F-28R) gave the highest combustion efficiencies, which varied from 70 to 95 percent.

3. At the favorable inlet-air condition (stable combustion), all fuels except the aromatic fuel with a high boiling temperature (aromatic solvent) gave combustion efficiencies above 90 percent for the range investigated.

Page 10: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

!I? NACARMNo.FX.30 9

4. The spread in altitude operational limit am- the qux$8 for all engine speeds vexled frcm 2OCO to 5000 feet with th& aromatic fuel of low boiling temperature (benzene) permitting the highest altitude limit at rated engine speed. A higher altitude operational' limit was permitted by AN-F-32 than by AN-F-2SR.

Flight Propulsion Research Laboratory, National Advisory Committee for Aeronautics,

Cleveland, Ohio.

1. Zettle, Sugeue V., Holz, Ray E., and Dittrich, R. T.: Effect of Fuel on Perf ommnce of a Single Ccmbuetor of an I-16 Twbojet Engine at Simulated Altitude Condition8. NACA RM No. E7A24, 1947.

2. Tiscbler, Adelbert O., and Dittrich, Ralph T.: Fuel Inveatiga- tion in a Tubular-Type Ccmbustor of a Turbojet Engine at Simulated Altitude Conditiona. NACA RM No. E7F12, 1947.

I

d

3. CbildB, J. Howard, McCafferty, Richard J,, and Surine, Oakley W.: Fffezt Ccp Combuetor-Inlet Conditions on Perforaraace of an An.nuLsr Turbojet ConibUBtOr. NACA TN No. l-357, 1947.

4. Turner, L. Richard, and Lord, Albert M.: Thermodynamic Charts for the Computation of Cmbustion and Mixture Temperatures at cotlatant Pre8sure. NACA TN No. 1086, 1946.

Page 11: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

Air-floe straightener

Explosion diaphragm

Flaor lsvsl

Observation windows

Electrical combustion-air heater

r- Oriflcs Atmospheric or altitude exhaust-

Figure I. - Diagrammatic sketch of IO&* Inch-diameter annular combustor and auxiliary equipment.

A-A, 8-6, lnstrumentatlon planes.

Page 12: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

i J

2 + Thermocouple 0 Total-presrure tube

P

n static-pressure tap cl I I-

Section A-A IComburtor inlet1

Sectim B-E ICombustor outlet1

Atmospheric or

Figure 2. - CROSS Section Of 1%inch-diameter annular ccjnbustor showing auxiliary ductlng and location of tqperature' and pressure-measurlng instruments in lnstrumentatlon planes.

Page 13: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

t

Total-pressure rake (SectIon A-A I

Chrmnal-almel thermcouple bank

lssctlon B-B I

tble, 0.031-In. dim.

I roll-constantan Static-prassurs tap thermocouple ISections A-A, B-81 I ssct Ion A-A.)

Figure 3. - Construction and instrumentation detai Is of temperature- and pressure-measuring instru- ments.

4b + 7. .i

Page 14: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM No. E7L30 13

lwo f I t f I -rI I I I I I I I

/ / 1 spaclflc mass 1

/ N

msoret1cil combustim /I

/

600 Sf fiCl~C

T 1 ,-;- hm?oent .&-

.csl ocalbustlon

.snoJ Ll pointa rsprsa as: double-tall

600

8

200 250 300 350 400 450 600 I550 600 650 700

Best Lnput, B&lb liF

Page 15: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

14 NACA RM No. nL30

60 E- I- i t

40

30

20 2.0 2.2 2.4 2.6 2.8 3.0

Specif'lc mass air flow, lb/set-eq ft FLgure 5. - Relation of combustlcn efficiency to mass air flow for

several fuels at two values of heat input. Annular combuator diameter, 1% inches; inlet-air total pressure, 14.3 inches meruury absolute; inlet-air total temperature, 40° F.

l

Y

-.

t

Page 16: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM NO. E7L30 15

Y I I I I I t I I I I .hdJ t I 4.50 t I 1400 200 I

80 I I I

J.0”

Heat input., Btu/lb air

Figure 6. - Varlrtlon of averrge colnbuator temperature rise and ccxnbuatfcm afilelsnc~ dth heat in ut for asveral ruels and three veluea of ma** air flow.

j, hnulsr c-tar dL%mter,

log lnctles; inlet-air total preasura, 30.7 inches mercury abao1nts; inlet-rlr totu tanperrtura, 1600 F.

Page 17: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

I6 NACA RI.4 NO. E7L30

28R, batch 2 ial isoheptane

90

80

I I I I I I I I I I I I I I I I I I I 0 E

L I I ---- t - I I I -

QOt m ! I I I I I I I I I I I I j

1 I

3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 Specific mass a.Lr flow, lb/set-sq ft

Figure 7. - Relation of combustion efficiency to-mass air flow for several fuels at tm values of heat input. Annular combustor diameter, lg inches; inlet-air total pressure, 30.7 inches morcurg absolute; inlet-air total temperature, 160° F.

Page 18: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM 3F

r

i

J/ I I

I t I 6.01

AH-F-2SR. bat& 2 c-olll laoheptum AX-F-32 #

60 loo I.60 200 260 300 360 4cta Ksat Input, B&/lb LIr

Figure 8. - i

f

Vsrlatlon OP aNrage ccmbtmtor teqeratrrrs rise ui3 combustion efflcianoy tith heat ut for several fuels and three valnss of-s air flow. Aanul.ar oombutor dl8mmster.

1 Inches; lnlst-nir total pressure, 61.1 lnohsm rnssOur~ absolute; inlet-rlr tetel tanperrture, 2500 F.

Page 19: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

18 NACA RM No. E7I.30

1

AN-F-28R, batch 2 Commeralal lsoheptane

5.8 6.2 6.6 7.0 7.4 7.8 8.2 Specific mass air flow, lb/set-aq ft

Figure 9. - Relation of caubustion efficiency to mass air flow for neveral fuel.8 at two values of heat input. 1% inches;

Annular combustor diameter, inlet-air total pressure, 51.1 inches mercury absolute;

inlet-air total temperature, 2SO" F.

Page 20: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

NACA RM No. E7L30 19

36

32

28 0 U-F-28& batch 2

Aromatic solvent 24

40 50 60 70 80 90 loo Percentage rated simulated en&-m rotational speed

Figure 10. - R .~

Altitude operatimel lfmfts aa detern&m d by various fuels in a 1%~inch-diameter annular combustor. Inlet conditions varied rith altitude and rotational speed.

NACA - Lpo@y Eleld, V..

Page 21: RESEARCH MEMORANDUM - NASA · RESEARCH MEMORANDUM COMBUSTION-EFFICIENCY AND ALTTTUDE-LXMT INVESTIGATIONS ... benzene) and were found to vary fm 30 to 58 percent. At the mcderste inlet-air

: