高超声速磁流体发生器性能-研究 (1)

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

2、ramjetmodecanbesustainedtomuchhigherflightMachnumbers.Inthisscheme,theinletairmustbeionizedandhavehighelectricalconductivitytoattaineffectiveMHDinteractioninthegenerator.Inthisthesis,theflowcharacteristicsandchemicalnonequilibriumionizationintheMHDgeneratorundermagne

3、ticfieldaresimulatednumerically.Firstofall,threedimensionalMHDfive-equationmodelassociatedwithlowmagneticReynoldsassumptionwasusedtosimulatetheflowphenomenonforarectangularFaradaytypeMHDgeneratorwithsegmentedelectrode,andtheeffectsofloadfactors,intensityofmagneticfie

4、ldandthewidthoftheelectrodesontheperformanceofthegeneratorwereinvestigated.Theresultsshowedthattheelectricalpowerdensityreachedmaximumwhentheloadingfactorwas0.5,andwiththeloadfactorincreasestheslowingcapacityofthegeneratorwasreduced.Atthemagneticfieldstrengthof8T,ele

5、ctricalconductivitywas20mho/m,500mmlengthofthegeneratorcouldreducedtheMachnumberfrom6to3below,keepthetemperaturebelow800K,andpowergenerationcouldreachtheamountofmegawatt-scaleofpercubicmeteroftheduct.Secondly,inordertocomprehendtheperformanceofhypersoniccold-airMHDpo

6、wergeneratorswithionizationbyelectronbeams,theflowphenomenaofarectangularFaradaytypeMHDgeneratorwithsegmentedelectrodeweresimulatedusingthethreedimensionalMHDfive-equationmodelassociatedwithlowmagneticReynoldsassumptionandasimplemodelofbeam-generatedionization.Theeff

7、ectsofpowerspentonionizationontheresultsofionizationwasinvestigated，drawingthenumberdensityofelectronsandelectricalconductivityformedbytheionizationunderdifferentionizationspent.Theresultsshowedthatelectronbeamswerecapableofgeneratinganadequateconductivityincoldair.A

8、tlast,theperformancesofMHDgeneratorunderdifferentpowerspentonionizationisinvestigatednumerically.Whentheloadingfactoris0.5,electric