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RESEARCHMEMORANDUM”

INVESTIGATION OF INTERNALI

OF A 1OOO-POUND-THRUST

FILM COOLING OF EXHAUST NOZZLE

LIQUID-AMMONIA LIQUID-OXYGEN

&OCKET

By Andrew E.Abrarnson

LewisFlightPropulsionLaboratoryCleveland,Ohio

CUSSIFDID~

l%iuumerielcmtalmldmmtlonmff-tlnsti NatlmhlB-femecfGmUzdtOIWbauitib meacdncd M .ssPfOmSOwm,me m,u.s.c.,SECS.764ad 794,theImmmfsslonorramhtlonofwIdchh qnbumrtoanumutbrlzedperwnlaPrOMMtadWlaw.

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NATIONAL ADVISORY coMMITTEEjj ‘FOR AERONAUTICS “

WASHINGTON ~ ~ w

IT IU.CARM E52C26

●

IUYTIONAL.

ADVISORYCO14MXTE3FOR

RESEARCHMEMORANDUM

,.

AEROMDI’K!S

INW3STIGATIONOF INIEMKLFILMCOOIZNGOFEXHAUSTNOZZLEOFA

1OOO-POUND-THRUSTLI~-MM3NIli LJC/llD-OXYGENROCKET

ByAndrewE.Abrsmson

E, SUMM4RY.* *-”-

An investigateio~”&

-rnal filmcoolingoftheexhaustnozzleofa 1(MO-pound-@rust “._nia liquid-oxygenrocketenginewasundertaken.The@p~.&enJ$.Covereda rangeof oiidant-fuelratioswiththecombustion--e~essure varyingfrom220to 275poundspersquareinchabsolute~a~~d anhydrousliquida.uznoniawereusedascoolantstiththeco&E%tf’$pwconstitutingfromabout12to 25percentofthetotalflow. Kl!!#c&@3 wasinjecteduniformlyaboutthecir-cumferenceoftheno-e eadwzance. ,-

U’lw%’Withwateras.as ol$$?,”approxhately%6percentofthetotalpro-

pellantandcoolant~~w wasrequiredtofilm-cooltheentirenozzleandwithanhydrous~qqid snmonia,approximately19percentofthetotalflowwasrequired.~

..Themaximumspecificimpulseobtainedfromanuncooledrocket

enginewas207poun+secondsperpouredor83percentof thetheoretical .equilibriumspecificimpulse.Whentheentirenozzlewasfilm-cooledwithammonia,themaximumspecificimpulseobtainedwas162pound-secondsperpoundor only78percentofthespecificimpulseobtainedwitha correspondinguncooledengine.AlthoughtheperformmceoftheuncooledrocketenginewaElow,thisreductioninperformancewasof sufficientmagnitudetomakefilmcoolingoftheentirenoz-zleby annulartijectionof ammoniaatthenozzleentranceappesrundesirable.

INTRODUCTION

engines,inwhichhightemperaturesandaccompanyingdensitiesareencountered,oneofthemajorproblemsis

Inrockethighheat-fluxthatofprovidinga suitablecombustion&sniberandnozzle;apableofwithstandingtheadversetemperatureeffe@.sg._t’hemethodsOf COOliWthesecomponentsoftherocketenginewhichhavereceivedthemostemphasissxetranspirationcooling(references1 to 6),regenerativecooling,andfilmcooling.

2 NACARME52C269

InternalfilmcooMngisa promisingmethodofcoolingandappearsto offersomeadvantagesoverregenerativecooling,suchas simplicity”of designandlowweightofthrustchamber.Ingeneral,ifa rocketpropellantistobe a satisfactorycoolant,itmusthavethereqtiedheat-absorbingcapacity.Forregenerativecooling,theheat-absorbingcapacityofa propellantisdeterminedby theamountofheatitcanabsorbintheliquldstate;forfilmcooling,however,theheat-absorbingcapacityincludesnotonlytheheatthatcanbe absorbedintheliquidstatebutalsothelatentheatofvaporization.Whereastheheat-transferrateto a filmcoolantishigherthanthatto a regenera-tivecoolant,thelargerheat-absorbingca~cityofa filmcoolant,ingeneral,morethancompensatesfortheincreasedheat-transferrate.HencesomepropelJszrbsnotsuitableasregenerative.coolantsmaybeusedasfilmcoolants.Fora givenapplication,h~yever,thewrits ofeachmethodof coolingsretobe consideredandin“tiomerocketengines,a combinationofbothregenerativeandfilmcoolingisused.

Investigationsrelatingtofilmcoolingunderidealizedconditionsaregiveninreferences7 to 10. A ViSUd-StudyOf:theflOWCh.=ELC-terlsticsof Iiqtidfilmsovera r-e ofgas-stresmconditionsisgiveninreference7. Thestabilityofliqtidfilni2establishedbyaslot-typeliq,,dinjectororientedat differentan@es tothewald.isreportedinreference8 forvariousgas-strewconditions.Filmcool-ofa hydrogen-oxygenflametubewithwaterisreportedinreference9anda preliminarycorrelationoffilm-coollngheat-transferresultsobtainedatairtemperaturesto 2000°F ina 4-inch-diameterductwithwaterasa coolantisgiveninreference10. Applicationof filmcoolingtorocketenginesisreported”inreferencesU.to 13. A con-siderablereductionoftheheatloadtotheregenerativecoolantby -useoffilmcoolingwithwaterinanacid-anilinerocketengineisreportedinreferenceIl..Filmcoolingtheconioustionchsmberofanmmnonia-oxygenrocketwithwater,’smmnia,andethylalcoholwas

-.

reportedinreference12. Theperformanceoftherocketwiththecom-bustionchaniberfilm-cooledwithsmnoniawasas goodastheperformanceofa similaruncooledrocketengine.Filmcoolhgthenozzleof anacid-anilinerocketby injectingwaterthroughseveralindividualtijec-torslocatedatvariousstationsalongtherocketnozzleresultedinaconsiderablereductioninthenozzlewalltemperature(reference13).

Previousinvestigationshavenotdeterminedthefeasibilityofcompletelyfilmcoolingthenozzle.Thefivestigationreportedhereti-wasconductedattheNACALewis.laboratoryinorderto determinethispossibility.A 1000-pound-thrustliqpid-smmonia13x@d-oxygenrocketemployingannularinjectionofthecoolantatthenozzleentrancewasused.Waterandliquidammoniawereusedas coolants.Thenozzlewalltemperaturewasdeterminedby skinthermocouplesspottedontheoutsidesurfaceofthenozzleatthedesiredpositions.

—---

—-

....—L

—

-.—

NACARME52C26

SYMBOLS

F

1

ThefolZowingsynibolsareusedinthisreport:

engine thrust, lbforce

specificimpulseofrocketengine, thrust(lbforce)totalL@id flowrate(lb/see)

ratioof combustion-chambervolumetonozzlethroatarea,in.

codmstion-chaiberpressure,lb/sqb. abs

fuelflow,lb/see

liquid-coolantflow,

oxidantflow,lb/see

\

lb/see

APPARATUS

Therocketengineusedforthisinvestigation(fig.1) consistedof a propellantinjectorincorporatinga gunpowdersquibigniter,anuncooledcombustionchaxiber,a coolantinjector,anda thin-wallednozzle.A gas-pressurizedpropellantandcoolantfeedsystemwasused.ThecharacteristiclengthL* oftheenginewas42 inches.

Propellantinjector.- An impinging-setpropellantinjectorasshownonfigure2 wasused. It consistedof 24pairsof jetsofone-on-oneimpingementapproximately0.375inchfromtheinjectorface.

Ignitionsystem.- Thepropellantinjectorwasdesignedto incorpo-ratea gunpowdersquibigniterat thecenteroftheinjector.Thesquibwasignitedby electricpower.

Combustionchamber.- Thecombustionchamberwasmadeofmildsteelhavinga 4-inchinsidedismeterwithwalls3./2inchthickanda lengthof6.70inches.A flangefromthecotiustiohchambermountedtherocketmotortothethruststand.

Coolantinjector.- Thecoolantinjectorwasmountedbetweenthecombustionchamberandtheexhaustnozzle.Thei?ijectorprovidedasupplyannulusforthecoolantfromwhichthecoolmtflowedthroughanannui&slotto theinsidesurfaceofthenozzle,as shownonfigure3.Theslotwas0.010inchwideandinclined30°tothecenterlineof therocketandthusdirectedthecoolamtalongth6nozzlesurface.ItWSS

.-

.

4. < ,.Midt“” 2JACARME52C26

necessarytoprovidea lipon thecoolantinjectorto coverthejointof coolantin~ectcmandnozzle,as slightmisalinementofthecoolantinjectorandnozzleencounteredduringassenjblywouldotherwiseresultinnonuniformcoolant.distribution.

Exhaustnozzle.- Theconvergent-divergentexhaustnozzle,madeofstainlesssteel,3S shownonfime 4. Thenozzlehadthefollowingdimensions:wallthickness,0.095inch;throatdiameter,1.85inches;exitdiameter,3.69inches;exit-throatarearatio,3.96;convergenthalf-angle,30°;anddivergenthalf-angle)15°. Thedesignexpansionratiowas20.4.Onthenozzlewerespotted34 chromel-alumelskinthermocouplesarrangedinfourlongitudinalrowsatthepositionsgiveninthefollowingtable:

DistancedownstreamIhmiberof Circumferentialofnozzleentrance thermocouplesspacingof

(in.) thermocouples(deg)

—0.5 1 360.9 4 901.4 4 901.9 4 90a2.35 4 902.9 4 903.3 1 3604.3 4 905.3 4 906.1 4 90

%ocationofnozzlethroat

,

.—..

—

--.

——.

. .

—

Propellantsandcoolants.- L@.dd oxygenandanhydrousliquidsmmoniawereusedaspropellants.Anhydrousliquida?mnoniaandfiltered ““ ‘

.—

waterfromthecitymainswereusedas coolants.—

Instrumentation.- me yropelht flow._@smeasuredwithanaccu-.racyof1 percentby theuse ofa straingageattachedtoa counter-balancedweighingbeamwhichs~orted thepropellanttanks.Theout-putof thestraingagewasrecordedcontinuouslyas a functionoft--ona self-balancingpotentiometer.Coolantflowwasmeasuredwithanaccuracyof0.02poundpersecondby anarea-typeflowmeter.

Thethrustoftherocketenginewasmeasuredwithanaccuracyof10youndsbymeansofa straingageattachedtoa parallelogramthruststand;theoutput-ofthestraingagewasrecordedby a self-balancingpotentiometer.

—

,

.

.N-Pm.3J

NACARM E52C26.

Theoutputs

. .

of12 chromel-alumelthermocoupleswere. anaccuracyof0.125millivoltinthe10-millivoltrange

5

measuredtithby a recording

.

.

.

.

self-balancingpotentiometer.Theoutputsof 16oftheremainingther-mocoupleswererecordedbymeansofa single-channeloscillographinconjunctionwitha selectorswitchmaking10 contactsa second.Accu-racyof 0.2millivoltina 22-millivoltrangewasobtained.

Theccmibustion-chaniber5 poundspersquareinchbyrecorder.

pressurewasmeasuredwithm accuracyofmeansofa Bourdon-tubetypestrip-chart

In operatingtherocket,thesquibwasfirstignitedandthenpro-pelhntandcoolantflowswerestartedshmib%neously.If thenozzleremainedcon@etelycooled,therocketwasoperatedforapproximately15 secondssoasto obtainreliabledata.E thenozzle became over-heatedbecauseof insufficientcoolantflowor &propercoolantdis-tribution,therunwastemrlnatedwithin5 secondstopreventburnoutofthenozzle.

Reductionofperformancedata.- Allperformancedatawerecorrec-tedto a commoncombustion-chamberpressureof 250poundspersqmeinchabsoluteforpurposesof comparison.A plotof specific@ulseagainstcombustion-chsnberpressureobtainedfromreference14 showedthatthechangeintheoreticalspecificimpulsefora changeincombustion-chamberpressurefrom Pc,l to PC,2 couldbe approximatedby theeqmtion

fortherangeof

AI = 79.5

cotiustion-chsmber—encounteredinthistivestigation.

Pc 1log~PC,2

pressuresandoxidant-fuelratiosTheoxidant-fuelratiowascalcu-

latedlyneglectingthecoobt flow.~ coolantflowwasincludedinthedeterminationof thespecifichpulseandthusgavethethrustperpoundof cotiinedpropellantandcoolantflow.

Uncooledrocketperformance.- Theperformanceofanuncooledrocketengines3milartotheengineusedforthefilm-coolingrunswasdeterminedforpurposesof comparison.Thisuncooledrocketengineconsistedof thesamecombustionchambersndpropellantInjectorthatwereusedforthefilm-coolingruns.Thecoolsntin~ectorandthethin-wall.ednozzlewerereplacedwitha solid-comernozzle.Thechs2+ac-teristiclengthoftheuncooledenginewas35inchesas compredwith42 inchesforthefti-cooledengine. .

.—

6 NACARME52C26.

RESULTSANDDISCUSSION

me PerttientdataobtainedfromtherunsaretabulatedfitableI. -Theoxidant-fuelratiobyweightvariedbetween1.35and3.98.Theconibustion-chaniberpressurevsxiedbetween220and275poundspersquareinchabsoluteandthecoolantflowconstitutedfromabout12 to 25per-

#centofthetotalflow. m

CoolantResults

Nozzlewallte~erature.- Thewalltemperatureprofileof-thenozzlewhencompletelyfilm-cooledtithwaterisshownonfigure5(a).Alsoshownistheboilingpointofwatercorrespondingtothepres&revariationalongthenozzle.Thewalltemperaturerisesrapidlydown-streamofthecoolantinjectorto a value slightlybelowtheboilingpointofwaterandremainsslightlybelowtheboilingpointfortheremaininglengthofthenozzle.Thenozzlewalltemperatureprofileobtainedwithsmmoniaasa coolantisgivenonfigureS(b).Thewalltemperatureisapproximately100°F alongtheentirenozzle,whereastheboilingpointofammoniavariesfrom@ F atthenozzleentranceto -35°F attheexit.Walltemperaturesexceedingtheboilingpointofammoniawerealsoencounteredwhenammoniawasusedtofilm-cooltheconibustionchamberofa rocketengine(reference12). A possibleex@a-nationforthisphenomenonwasthata fuel-richlow-temperatureregionexistsnearthewallandthusgivesa regionhavinga lowdiffusionratewhichwouldtendtoallowsuperheatingoftheliquid.Anotherpossibleexplanationisthat,astheexhaustgasescontaina highper-centageofwatervapor,theliquidsmmmniaalongthewallcouldabsorbsomewatervaporandthuschangetowmnoniumhydroxide,whichhasahigherboilingpoint.Stillanotherpossibilityisthattheliqtidanmmniadoesnotcoverthenozzlesurfaceina continuousliqyidsheet~thatis,thefilmconsistsofa mixtureofvaporanddroplets.

Coolantflowreqtied to film-cooltheentirenozzle.- Fortherocketconfigurationusedinthisinvestigation,theminimumcoolantflowrequiredforfilmcoolingtheenttie-nozzlewithwaterwasapprox-imately16percentofthetotalflowandwithammonia,approximately19percentofthetotalflow.Forlowercoolantflows,theliqtidfilmterminatesupstreamofthenozzleexitandtheportionofthenozzlewhichisnotprotectedby a liquidfilmbecomesoverheated.

Theperformanceis shownonfigme 6oxidant-fuelratio.

PerformanceResults

obtainedforthevariouse~rimentalconditionstiwhichspecificimpulseisplottedagainstTheexperimentalspecificimpulseobtainedforthe

—.

—

—

— .—

.

.

.

——

b

—

.

NACARME52C!26 7●

Ng

N

uncooledrocketengineislow,a~proximately83percentof thetheo-reticalperformance.Thetheoreticalperformanceisforcompletecom-bustionat 250poundspersquareinchabsolutefollowedby shiftingequilibriumisentropicexpamsionto 1 atmxphereabsoluteTressure.Theexperimentalspecificimpulseobtainedwhentheentireexhaustnozzlewasfilm-cooledwasconsiderablylowerthanthatobtainedfortheuncooledengine.Theuseof ammoniaas a coolantresultedinaslightlyhigherspecificimpulsetk wasobtainedwithwaterasaCoolx!at.

Amaxhum specificiqml.seof 207pound-secondsperpoundwasobtainedfortheuncooledengine,whereasonly78percentof thisvalueor 162pound-secondsperpoundwasobtainedwhentheentireexhaustnozzlewasfti-cooledwithammonia.Althoughtheperformanceoftheuncooledrocketenginewaslow,thisreductioninperformancewasof sufficientmagnitudetomakefilmcoo13ngoftheentirenozzlebyannularinJectionof.snmmniaat thenozzleentranceappearundesirable.

COITCLUDIKG~

Inasmuchasfi3mcoolingof theenttieexhaustnozzleby injec-tionof thecoolantat thenozzle entranceresultsinan intolerablelossinperformance,othercoolingaidsormethodsforthenozzle,

. suchasregenerativecoolingor ceramicliningsor coatings,maybesought. Also,thereisa possibilityoffilmcoolinga portionoftheconvergentsectionofthenozzlewitha reactivecoolantwithout

-’ adverselyaffecthgtheperfornm.nceoftherocket.Eromconsiderationoftheresidencetimeof a particleintheexhaustnnzzle(fig.7),itisevidentthstifa giv,entimeisrequiredforthevaporizedcooLurt-to diffuseandburn,thenonlythatwhichvaporizesupstreamofa givenstationalongthenozzlewilJeffectivelyburninthenozzleandenhancetheperformanceoftherocket.Further,heatthatisreleasedatlowpressureinthenozzle doesnothaveasgreatanexpansionratioandcan-notcontributeasmuchtoperformanceaswouldbe possibleif itwerereleasedintheconibustionchsmber.Thefactthattheperformanceobtainedwhen a reactivecoolantwasused,however,exceededthatobtainedfromem inertcoolant(fig.6) tidicatesthatperformancegainwasobtainedfromsomeofthereactivecoolant.

SUMMARYW RESULTS

*

.

Internalfilmcoolingofthenozzleof a 1000-pound-thrustliquid-smmnialiquid-o~genrocketenginewitha 42-@h characteristiclengbhwasinvestigatedwithconibustion-chsniberpressuresfrom220to275pounds~ersquareinchabsoluteovera rangeof oxidant-fuel

8

ratiosfrom1.35~o3.98.coolantswiththecoolantcentofthetotalflow.

-NACARM E52C26.-.-=.-:.-‘--*#: -=,.

Waterandliqpidazmnoniawereusedasflowconstitutingfromabout12to 25per- .—

Theresultsoftheinvestigationcanbe sumnsrizedasfollows:k

1.Theentirenozzleoftherocketenginewasfilm-cooledwith*n.

waterandtithliquidanunoniaby uniformannularinjectionof theN

coolantatthenozzleentrance.Whenwaterwasusedasa coolant,16percentofthetotalflowwasrequiredto cooltheentirenozzle.Withliquidanmmniaasa coolant,19percentofthetotalflowwasrequiredto,cooltheentirenozzle.

2.Themaximumspecificimpulseobtainedwhentheentirenozzlewasfilm-cooledwithliquidammoniawas162pound-secondsperpoundor 78percentofthema.xlmumspecificimpulseobtainedfroma correspon-dinguncooledengine.Thisreductioninperformanceisof sufficient .magnitudetomakefilmcoolingoftheentirenozzleby annularinjec-

—

tionofamnoniaatthenozzleentranceappesrundesirable.

LewisFlightPropulsionLaboratoryNationalAdvisoryCommitteeforAeronautics

Cleveland,Ohio.

REFERENCES

1.Duwez,Pol,andWheeler,H.L.: PreliminaryExpertientsonthe.

Sweat-CoolingMethod.Prog.Rep.No.3-13,PowerPlantLab.pro~.No.MX527.JetPrag.Lab.,C.I.T.,JiIly18,1946. (ATSCContractNo.W-33-0380-ac-4320.)

2.Duwez,Pol,andWheeler,E.L.,Jr.: An ExperimentalStudyofSweatCoolingwithNitrogenandHydrogen.Prog.Rep.No.4-47,—.

PowerPlantLab.Prod.No.MX801,JetProp.Lab.,C.I.T.,Sept.24,1947. (AMCContractNo.W-535-ac-20260,OrdnanceDept.ContractNO.W-04-2004RD-455.)

3.Duwez,Pol,andw’heeler,H. L.,Jr.: HeatTransferMeasurementsina NitrogenSweat-CooledPorousTube.Prog.Rep.No.4-48,PowerPlantLab.Proj.No.MX301,JetProp.Lab.,C.I.T.,Nov.6, 1947.(AM!ContractNo.W-535-ac-20260,OrdnanceDept.ContractNo.W-04-200-CRD-455.)

4.Rannie,W. D.: A SimplifiedTheoryofPorousWallCooling.Prog.Rep.No.4-50,PowerPlantLab.Proj.To.MX801,JetProp.Lab.,C.I.T.,NOV.24,1947. (AMCContractNo.W-535-ac-20260,OrdnanceDept.ContractNo.W-04-2004RD-455.)

a

.

2T NACARM E52C26●

5..

xlPnQ

6.

.

.

7.

8.

9.

10.

Il.

12.

13.

14.

1

oanright,RichardB.:pirationCoolingof

9

~eliminaryExperimentsof GaseousTrans-RocketMotors.Prog.Rep.No.1-75,Power

PIantLab.Proj.No.MX.801,JetProp.Lab., C.I.’T., Nov. 24,M48.(AMCContractNo.W-535-ac-20260,OrdnanceDept.ContractNo.W-04-200-ORD-455.)

Jheeler,H. L.,Jr.: TheInfluenceofWallWterialontheSweat-CoolingProcess.Prog.Rep.No.4-90,JetMay3,1949. (OrdinanceDept.ContractNo.

Kinney,GeorgeR.,andAbramson,AndrewE.:larLiquidFlowwithCocurrentAirFlowinNACARME51C13,1951.

prO~. Lab., C.I.’I’., .W-04-200-QRD-455.)

InvestigationofAnnu-HorizontalTubes.

Zucrow,M. J.,Beighley,C. M.,andKhuth,E.: ProgressReportontheStabilAtyofLiqtidFi3nsforCoolingRocketMotors.Tech.Rep.No.23,PurdueUniv.,Nov.~, 1950. (ContractN6-ORI-1O4,TaskOrderI,NR 220-042,Phase7,Pro3ectSquid.)

Schurman,GlennA.: An InvestigationofFilmCoolingina Flameltibe.Prog.Rep.No.1-74,PowerPlantM. Proj.No.MX801,JetProp.Lab.,C.I.T.,June30,1948. (MC ContractNo.W-535-ac-20260,OrdnanceDept.ContractNo.w-04-2oo-om-455*)

Kimney,GeorgeR.,andSloop,JohnL.: InternalFiJmCoO1-ingExperimentsina 4-InchDuctwithGasTemperaturesto 2000°F.NACARME50F19,1950.

Boden,RobertH.: HeatTransferinRocketMtors andtheApplica-tionofFiImandSweatCooling.A.S.M.E.Trans.,vol.73,no.4,May1951,pp.385-390.

Morrel.1,Gerald:Investigationof ~ternalFilmCmlingof1000-Pound-ThrustLiqyid-lmmmnia- Liquid-OxygenRocket-EngineCcmibus-tionChamber.NAC!ARME5U304,1951.

Sloop,J.L.,andHnney,GeorgeR.: hternal-Fi3mCoolingofRocketNozzles.NACARME8A29a,1948.

Winternitz,P.F.: SumaryReportonTheoretical,LaboratoryandExperimentalInvestigationsofHighEnergyPropellants.Ammonia,vol.II,Rep.No.RMI-293-S7,ReactionMotors,Inc.,Oct.30,1950. (Bur.Aero.,NavyContractNOa(s)9469.)

.

Run

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OxiaentfllmW.

(lb/see)

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TAmEI— PlRFOFu4AwmIM!I!AFRCM RWKET-lWZ2LE FIIX-CO- EXJ?ERIMENI’S

Fuel flow coolantmlnletConibu6tlcm-clmrberkLdmlt.-Wf

Cocib?ntflowflmn pressure fuel ratio loowJ( Wo+wf+wz)

(lb/see) ‘1(;) P= neglecting (percent)

(Ib/see) (lb/sqfi. abs)coolantwJwf

ICcd.mlt, Wati

J-L1 2.58 1.872 2.60 1.923 2.65 1.554 2.51 1.675 3.00 1.716 2.90 1.89

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Coolmt, anhydroueliquid enuncmia

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presmm d 250 Ib/aqin. abs.

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Fi@re 1. - Rocket engine used for investigation of nozzle film cmlhg.

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Fmlre 2. - Propellant InJector.

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Rocketnazzlecontour\ / ‘

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Figure5. - TypicalnozzleSymbolsreferto

Distancealongnozzle,in.

(a)Coolant,water.

walltemperature profile fcm entirenozzlefLlm-cooled.clifferent longitudinal rows of thermocouples.

,

7

.

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. .

0 1 2 3 4 5

Distance almg nc.mlo, In.

(b) Coolant, Uquid ammnia.

Et—

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Figure 5. - ccmdudad. Tgpical nmda mu tqparature mile fm mttie noazls film-

cooled. 2@01E rafm to difr~ent lmgitudinel row of thamocovplm.

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zII Uncooled rocket

o Nozzle film-cooled with mmoniaA Nozzle film-cooledwith water

– – -83 percent of theoretical —specific @mil.ae

Canbuation-chambercmidant-fuelratio, Wok

Figure 6. - COIIQZriBOll Of ptX’fOJ31WlCe of uncooled rocket engine with parfornmnce obtained when

dxmat nozzle waa film-cooled with water m liauld annnmia. E@eclflc Inumlae valuee ace

corrected to ccenbuation-chamberpressore of 250-pJUndBper squ&e inch ab;olutewith expansionto 1 atmosphere. Coolmt flow variea frau 16.9 to 24.4 percent of total flow.

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Rocket

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Co?lta.lr IHozzleexit

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Dlstencealmg rocketrotor,in.

Figme 7..-Rirticl.ereddmce timefromnomle exitvith asmqtion of unifcnmone-dlmensimMIfum. (bal)wtion.chemberpreemre, 254)poudx per BquareM absolute;totaltau@rature,45600F.