柴油机三维流体流动数值分析

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1、西南交通大学硕士学位论文柴油机三维流体流动数值分析姓名：周海磊申请学位级别：硕士专业：动力机械及工程指导教师：李人宪20080501西南交通大学硕士研究生学位论文第1I页AbstractThequalityofairflowfieldincylinderofdieselenginewilleffecttothecombustionprocessandfurthertodynamicalperformance，fueleconomyandemissionperformance．Therefor，dieselengineresearcherspayspecial

2、attentiontotheresearchallthetime．Becausethereismultidimensional、multicomponent、complexandtransientprocessinairflowinsidethecylinderofdieselengine，itisdifficulttomonitoroverallairflowconditionincylinder．Withtheimprovementofcomputerpoweranddevelopmentofcomputationalfiuiddynamics，many

3、scholarsdevotetOresearchingfluidflowandheattransferindieselwiththemethod0tcFD．Inthispaper，a280mmdiametercylindermodelofalocomotivedieselenginewassetup．Basedonthismodel，temperaturefield，velocityfieldandpressurefieldinthecylinderwassimulatedbynumericalmethodsunderdifferentparameter．T

4、hesimulationwasbasedoncontinuityequation，momentumequationandenergyequationsinfluiddynamics；k-stwo—equationturbulencemodelwasusedtosimulateturbulenceflowincylinder．FinitevolumemethodwasusedtOdiscretizethecomputedarea；Upwinddifferencingschemewasusedinthenumericalcomputation，andSIMPLE

5、algorithmwasadoptedtocouplethevelocityandpressureinflowfield．Becauseintakeandexhaustvalvesaswellaspistonareinastateofmovementwhendieselenginewasworking，movingmeshconservationequationswasusedinthesimulation．Toanalysisairflowincylinderindetail；thesimulationwasdoneindifferentstrokesof

6、thedieselengine．Besidesthat，thedistributionofgasspeed，temperatureandpressureincylinderweresimulatedwithdifferentrunningspeed、differentvalvetiminganddifferentmodularconstructionofMPCsystem．Thecalculationresultsshows：theintakeswirliSformedfromtheoutsidetotheinside，smalltobig，whilethe

7、bigswirliseccentricity；theexhaustswirlisformedfromtheflowwhirlwhichgeneratedbyvalveresistance，andthemaximumvelocityoftheflowfocusawayfromthevent；thespeedofthedieselenginehasgreatinfluenceontheflowscharacteristicsin—cylinder．Theaveragetemperature，averagepressureandturbulentkineticen

8、ergyathighengine西南交通大学硕士研究