简介:摘要:提升滑油泵设计能力是提高滑油泵研发能力的源头,传统上滑油泵性能依赖试验结果验证,而此验证过程将极大延缓研发周期,为改善和提高产品设计能力,本文基于Simerics仿真平台对航空内啮合齿轮泵和外啮合齿轮泵开展CFD计算分析,对内啮合齿轮泵流体压力、速度矢量、转子厚度和偏心距进行影响性分析,对外啮合齿轮泵的转速、进口压力和出口压力进行影响性分析。
简介:NumericaltechniquesplayanimportantroleinCFD.Someofthemarereviewedinthispaper.ThenecessityofusinghighorderdifferenceschemeisdemonstratedforthestudyofhighReynoldsnumberviscousflow.Physicalguidelinesareprovidedfortheconstructionofthesehighorderschemes.Toavoidundulyadhoctreatmentintheboundaryregiontheuseofcompactschemeisrecommendedbecauseithasasmallstencilsizecomparedwiththetraditionalfinitedifferencescheme,BesidespreliminaryFourieranalysisshowsthecompactschemecanalsoyieldbetterspaceresolutionwhichmakesitmoresuitabletostudyflowwithmultiscalese.g.turbulence.Otherapproachessuchasperturbationmethodandfinitespectralmethodarealsoemphasized.Typicalnumericalsimulationswerecarriedout.ThefirstdealswithEulerequationstoshowitscapabilitiestocaptureflowdiscontinuity.TheseconddealswithNavier-Stokesequationsstudyingtheevolutionofamixinglayer,thepertinentstructuresatdifferenttimesareshown.Asymmetricbreakdownoccursandalsotheappearanceofsmallvortices.
简介:Applicationsofcomputationalfluiddynamic(CFD)tothemaritimeindustrycontinuetogrowwiththeincreasingdevelopmentofcomputers.Numericalapproacheshaveevolvedtoalevelofaccuracywhichallowsthemtobeappliedforhydrodynamiccomputationsinindustryareas.Hydrodynamictests,especiallyplanar-motion-mechanism(PMM)testsaresimulatedbyCFDsoftware-FLUENT,andallofthecorrespondinghydrodynamiccoefficientsareobtained,whichsatisfytheneedofestablishingthesimulationsystemtoevaluatemaneuverabilityofvehiclesduringtheautonomousunderwatervehicleschemedesignstage.Theestablishedsimulationsystemperformedwellintests.
简介:Thispaperdevelopsahypersonicaerothermalsimulationmethodformissileslotflow.ThefinitevolumemethodofstructuregridsolverisdevelopedforsolvingEulerandNavier-Stokesequations.ThesolverincludesPark'stwotemperaturemodelandtheairmulti-speciesreactionmodel.Thesecond-orderaccuracyTVDnumericalmethodwasdeducedtocomputethehypersonicaeroheatingwhichimprovesthecomputationalefficiency.Computationalresultsaregiventoshowthehighaccuracycomparingtotheexistingexperimentaldata.
简介:NowadaysComputationalFluidDynamics(CFD)softwareisadoptedasadesignandanalysistoolinagreatnumberofengineeringfields.Wecansaythatsingle-physicsCFDhasbeensufficientlymaturedinthepracticalpointofview.ThemaintargetofexistingCFDsoftwareissingle-phaseflowssuchaswaterandair.However,manymulti-physicsproblemsexistinengineering.Mostofthemconsistofflowandotherphysics,andtheinteractionsbetweendifferentphysicsareveryimportant.Obviously,multi-physicsphenomenaarecriticalindevelopingmachinesandprocesses.Amulti-physicsphenomenonseemstobeverycomplex,anditissodifficulttobepredictedbyaddingotherphysicstoflowphenomenon.Therefore,multi-physicsCFDtechniquesarestillunderresearchanddevelopment.Thiswouldbecausedfromthefactsthatprocessingspeedofcurrentcomputersisnotfastenoughforconductingamulti-physicssimulation,andfurthermorephysicalmodelsexceptforflowphysicshavenotbeensuitablyestablished.Therefore,innearfuture,wehavetodevelopvariousphysicalmodelsandefficientCFDtechniques,inordertosuccessmulti-physicssimulationsinengineering.Inthepresentpaper,Iwilldescribethepresentstatesofmulti-physicsCFDsimulations,andthenshowsomenumericalresultssuchasiceaccretionandelectro-chemicalmachiningprocessofathree-dimensionalcompressorbladewhichwereobtainedinmylaboratory.Multi-physicsCFDsimulationswouldbeakeytechnologyinnearfuture.
简介:Acombustionmodelofalarge-scalesupercriticalcirculatingfluidizedbed(CFB)boilerwasdevelopedforcomprehensivecomputational-fluid-dynamicsanalysis.Themodelincorporatesgas-solidhydrodynamics,coalcombustion,heattransferonheatexchangesurfacesinthefurnace,andheattransferbetweenfumaceandworkingmediumintheheattransfertubes.Insimulatingthedenseanddilutephasesinthefumace,thegas-solidhydrodynamicsisbasedontheEuler-Eulermodelandenergy-minimizationmultiscaledragmodel.Coalcombustionentailsevaporation,devolatilization,charcombustion,gashomogeneousreaction,andpollutantemission.Thecoefficientofheattransferbetweengas-solidandthewaterwallisestimatedusingtheclusterrenewalmodel,andforradiation,thediscreteordinatemodelisused.Moreover,thermohydraulicprocessesinthemembranewallarealsoineludedintheheattransferprocess.Themodelwassuccessfullyappliedinsimulationsofa350-MWsupercriticalCFBboiler.Detaileddistributionsofsolidsconcentration,oxygen,heatflux,andworkingmediumtemperatureintheboilerfurnacearepresented.
简介:摘 要:本文是对某TMF型(上冷冻、下冷藏式)风冷冰箱的冷冻风道进行CFD仿真,得到冷冻风道的流线图,压力云图,风道各出风口的出风量和占比数据。分析出,风扇与风道腔体边界距离偏小,空气撞击在边界上易形成局部涡流,增大风道局部阻力;风道左上,右上两出风口风量不均匀,右上出风口相对左上出风口流线密度有降低,出风口风速降低。并进行实验测试风道的各出风口风量,同仿真结果进行对比,测得各处风口风量趋势和仿真结果一致。
简介:InthisarticletheUDFscriptfileintheFluentsoftwarewasrewrittenasthe'connectingfile'fortheFluentandtheANSYS/ABAQUSinorderthatthejoinedfilecanbeusedtodoaero-elasticcomputations.InthiswaythefluidfieldiscomputedbysolvingtheNavier-Stokesequationsandthestructuremovementisintegratedbythedynamicsdirectly.Ananalysisofthecomputedresultsshowsthatthiscoupledmethoddesignedforsimulatingaero-elasticsystemsisworkableandcanbeusedfortheotherfluid-structureinteractionproblems.
简介:针对有关毒气急性中毒研究只能根据经验公式和接触限值划定危险区域进行定性评估的现状,提出结合毒气泄漏CFD数值模拟与中毒剂量反应模型进行中毒定量评估的方法。通过CFD计算泄漏毒气的实时浓度场,根据浓度场和暴露时间确定人员暴露剂量,最后根据剂量反应模型确定人员死亡百分比。以某硫黄回收装置的硫化氢泄漏为例,建立CFD模型。设置距地面高1.5m,与泄漏源水平距离分别为100m、200m、300m、400m、500m的5个监测点作为工作人员的急性中毒地点,模拟分为构建初始风场、硫化氢泄漏及随风场扩散3个阶段,根据CFD求解得出的监测点的硫化氢实时浓度场并结合中毒剂量反应模型对监测点人员中毒死亡风险进行定量评估。研究表明,基于CFD的毒气泄漏中毒定量评估技术能对泄漏区域任意位置、任意时刻的人员中毒风险进行定量评估,弥补了目前大多定性评价方法的不足。