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1、808J.PROPULSION,VOL.13,NO.6:TECHNICALNOTES11Reynoldsnumber.TheIspefciencyistheratiooftheactualOff-DesignPerformancePredictionIsptotheinviscidIspofSingle-SpoolTurbojetsIspactualUsingGasdynamicsh=(4)IspidealMirzaF.Baig*andisthusameasureofviscouslosses.InviscidIs
2、pvalueswerecalculatedwiththeTDKcode.9ThenozzlethroatReynoldsAligarhMuslimUniversity,Aligarh202001,IndianumberisdenedasandH.I.H.Saravanamuttoo†Re*=2mÇ/pr*mc(5)CarletonUniversity,Ottawa,OntarioK1S5B6,Canadawherer*isthenozzlethroatradius,andmcisthechamberviscosit
3、y.Foragenerallyconstantpressureinthenozzlethroat,fasterkineticsproducehighertemperaturesandlowerdensi-Nomenclatureties.TheReynoldsnumberandhvaluesdecreaseasdensityA=areaofexhaustnozzledecreases,indicatingincreasingboundary-layerthicknessandCp=specicheatatconst
4、antpressureviscouslosses.Table2showsthatthenetIspactuallyincreasesM=Machnumberwithincreasingkineticrate.Theseoppositetrendsindicatethatm=massowkineticlossesarethedominantlossmechanism.IncreasingtheN=enginemechanicalspeedrecombinationratereducesthekineticlosses
5、,butincreasestheP=pressurenozzleviscouslosses,thusmoderatingtheIspimprovement.R=gasconstantBecauseofthelowinitialdegreeofdissociation,theuncer-T=temperaturetaintyinkineticrateonlyproduceda0.2%Ispuncertaintywith«c=compressorpressureratioTc=2780KandPc=345kPa.Att
6、helowestchambertem-hc=polytropiccompressorefciencyperature(2220K),theIspuncertaintycausedbythekineticratehm=mechanicalefciencyisnegligible.Halvingthechamberpressurefrom345to173ht=polytropicturbineefciencykPaat2780Khalvedthethrustandmassowrate,slightlyc=Tt4/Tt2
7、/(Tt4/Tt2)desdecreasedtheIsp,andproduceda0.2%Ispuncertainty.There-fore,chamberpressurehasonlyaslightimpactontheinu-Subscriptsenceofhydrogenkineticrateuncertainty.a=airBasedonthisinvestigationandtherecommendationsofdes=design6t=totalotherresearchers,theBaulchet
8、al.kineticratesarerecom-mendedasnominalratesforfuturenumericalpredictionsof0=ambientatmospheresolarthermalrocketperformance.I.IntroductionAcknowledgmentFF-DESIGNperformanceofaeroen
