高超声速磁流体发生器性能-研究

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1、高超声速磁流体发生器性能研究AbstractThefundamentalideaofMHDenergybypassistouseMHDenergyconversionprocessestoextractandbypassaportionoftheintakekineticenergyaroundtheburner.ItispossibletoincreasethefreestreamMachnumberforwhichtheflowremainslowMachnumberandthroughouttheburner,andtheramjetmodecanbesus

2、tainedtomuchhigherflightMachnumbers.Inthisscheme,theinletairmustbeionizedandhavehighelectricalconductivitytoattaineffectiveMHDinteractioninthegenerator.Inthisthesis,theflowcharacteristicsandchemicalnonequilibriumionizationintheMHDgeneratorundermagneticfieldaresimulatednumerically.Firs

3、tofall,threedimensionalMHDfive-equationmodelassociatedwithlowmagneticReynoldsassumptionwasusedtosimulatetheflowphenomenonforarectangularFaradaytypeMHDgeneratorwithsegmentedelectrode,andtheeffectsofloadfactors,intensityofmagneticfieldandthewidthoftheelectrodesontheperformanceofthegener

4、atorwereinvestigated.Theresultsshowedthattheelectricalpowerdensityreachedmaximumwhentheloadingfactorwas0.5,andwiththeloadfactorincreasestheslowingcapacityofthegeneratorwasreduced.Atthemagneticfieldstrengthof8T,electricalconductivitywas20mho/m,500mmlengthofthegeneratorcouldreducedtheMa

5、chnumberfrom6to3below,keepthetemperaturebelow800K,andpowergenerationcouldreachtheamountofmegawatt-scaleofpercubicmeteroftheduct.Secondly,inordertocomprehendtheperformanceofhypersoniccold-airMHDpowergeneratorswithionizationbyelectronbeams,theflowphenomenaofarectangularFaradaytypeMHDgen

6、eratorwithsegmentedelectrodeweresimulatedusingthethreedimensionalMHDfive-equationmodelassociatedwithlowmagneticReynoldsassumptionandasimplemodelofbeam-generatedionization.Theeffectsofpowerspentonionizationontheresultsofionizationwasinvestigated，drawingthenumberdensityofelectronsandele

7、ctricalconductivityformedbytheionizationunderdifferentionizationspent.Theresultsshowedthatelectronbeamswerecapableofgeneratinganadequateconductivityincoldair.Atlast,theperformancesofMHDgeneratorunderdifferentpowerspentonionizationisinvestigatednumerically.Whentheloadingfactoris0.5,ele

8、ctric