Q/SZJ191001-2017乘員艙除霜除霧仿真分析規(guī)范SpecificationofCabinDefrostandDefogSimulation20XX20XX-06-30實(shí)施20XX-05-29發(fā)布XXXX汽車工程技術(shù)有限公司發(fā)布Q/SZXX-X-2017乘員艙除霜除霧仿真分析規(guī)范范圍本標(biāo)準(zhǔn)規(guī)定了術(shù)語(yǔ)和定義、乘員艙除霜除霧仿真分析及結(jié)果處理方法。本標(biāo)準(zhǔn)適用于CAE部門乘員艙除霜除霧仿真分析。規(guī)范性引用文件無(wú)。術(shù)語(yǔ)和定義無(wú)。摘要Abstract本規(guī)范規(guī)定了乘員艙除霜除霧仿真分析建模、邊界條件處理及后處理方法。本規(guī)范適用于XX汽車公司開發(fā)的乘用車CFD建模及分析。Thisproceduredefinescabindefrostanddefogsimulationmodeling,boundaryconditionsandpost-processingmethodforvehiclebody.It’sapplicablefortheXXautomotivecompanypassengercarsCFDmodelingandanalysis.流程圖ProcessFlowDiagram圖1CFD分析流程圖Fig.1CFDanalysisschedule工具描述ToolDescription仿真分析過(guò)程中需要用到的如下軟件:前處理(Preprocessors):Hypermesh求解器(AnalysisCode):StarCCM+后處理(Postprocessors):StarCCM+建模過(guò)程ModelingProcedure單位Units分析中所用單位制如下所示:Theunitsusedintheanalysisareasfollows:力(Force) 牛頓(N)質(zhì)量(Mass) 千克(Kg)長(zhǎng)度(Length) 米(M)時(shí)間(Time) 秒(Second)幾何數(shù)據(jù)處理GeometryDataTreatment除霜除霧分析模型所需數(shù)據(jù)主要由乘員艙內(nèi)CAS、全車玻璃、AB區(qū)及側(cè)窗視野區(qū)域劃線、除霜風(fēng)管、坐椅、地毯等數(shù)據(jù)構(gòu)成，見圖2。ForCabindefrostanddefoganalysis,thegeometrydatashouldincludecabinCAS,glasses,A/Bzoneandsidewindowviewzoneboundary,defrostducts,seatsandcarpet,asshowninFig.2.圖2除霜除霧分析幾何模型示意圖Fig.2DefrostandDefoganalysisgeometrymodel部件分組ComponentsDividing幾何數(shù)據(jù)收集好后，按照產(chǎn)品名稱分組，并采用Wrapper功能進(jìn)行網(wǎng)格包絡(luò)，找到最大內(nèi)部面。除霜管道、格柵、前擋風(fēng)玻璃和前側(cè)窗的位置處網(wǎng)格要求足夠細(xì)密，保持好玻璃形狀、視野區(qū)，管道及格柵特征線保留完整；模型進(jìn)口形狀盡量規(guī)則，乘員艙中后部網(wǎng)格尺寸可適當(dāng)增大。Theproductshouldbedividedintoservalpartsafterthegeometrydatacollected,andwrappedthegeometrysurfacebywrappertofindoutthebiggestinteriorsurface.Thesurfacemeshofthedefrostducts,grilles,frontwindshieldandfrontsidewindowshouldbeverysmooth,andkeeptheglassesshapeandviewingzone.Keeptheductsandgrillesfeaturelinesfine,andtheinletshapeshouldberegular.Themeshsizeofthemiddleandrearpartsofcabincanbebigger.模型建立ModelCreating處理模型首先需要選擇網(wǎng)格劃分方式，這里選擇Wrapper對(duì)面網(wǎng)格進(jìn)行處理，形成單一封閉腔體；選擇Remesher對(duì)新生成面網(wǎng)格進(jìn)行優(yōu)化；最后選擇Trimmer和LayerMesher生成體網(wǎng)格用于計(jì)算求解，見圖3。Youneedchoosethemeshmethodfirstlywhendealingwiththemodel,choosingwrapperheretodealingwiththesurfacemesh,andgenerateaclosevolume,thenchooseremeshertooptimizethenewgeneratedsurfacemesh.Afterthat,youchoosetrimmerandlayermeshertogeneratethevolumemeshandrunsimulation.圖3網(wǎng)格劃分方式選擇示意圖Fig.3Meshmethodchoosing加密區(qū)域設(shè)置IntensiveMeshZoneSetting利用Block模塊設(shè)置加密區(qū)域，對(duì)前擋風(fēng)玻璃、側(cè)窗、除霜管道和格柵進(jìn)行局部加密，加密尺寸0.003～0.006m。SettingintensivemeshzoneusingBlockmodule,tomakeintensivemeshingforfrontwindshield,sidewindow,defrostductsandgrilles,themeshsizecanbe0.003~0.006m.邊界條件BOUNDARYCONDITIONS計(jì)算模型的設(shè)置表1計(jì)算模型設(shè)置Sheet1Computationalmodelsetting運(yùn)動(dòng)方式MotionStationary材料MaterialGas流動(dòng)形式FlowSegregatedFlow瞬態(tài)/穩(wěn)態(tài)選擇TimeSteady流體形態(tài)選擇EquationofStateConstantDensity粘渦模型ViscousRegimeTurbulent湍流模型TurbulentReynolds-AveragedNervier-Stokes雷諾應(yīng)力湍流模型選擇Reynolds-Averaged

TurbulenceRealizableK-EpsilonTwo-Layer壁面函數(shù)k-EpsilonTwoLayerAlly+WallTreatmentTwoLayerAlly+WallTreatment附加選項(xiàng)OptionalPhysicsModels如果網(wǎng)格質(zhì)量較差，可以把CellQualityRemediation選擇上，此選項(xiàng)有利于計(jì)算收斂，但會(huì)影響計(jì)算速度。模型設(shè)置完成后應(yīng)該如下圖所示：Themodelsettingcompletedshouldbeshownasbelow:圖4計(jì)算模型選擇示意圖Fig.4Computingmodelselection邊界條件的設(shè)置表2邊界條件Sheet1Boundaryconditions邊界名稱邊界類型數(shù)值進(jìn)口massflowinlet300m^3/h(以實(shí)際風(fēng)量為準(zhǔn))出口pressureoutlet0pa壁面wall壁面無(wú)滑移性能要求PERFORMANCEREQUIREMENTS前風(fēng)擋及側(cè)窗玻璃壁面內(nèi)側(cè)的風(fēng)速達(dá)到目標(biāo)值，如表3所示。Theairflowvelocitiesonthefrontwindshieldandsidewindowwallmeetthetarget,asshowninsheet3.表3分析評(píng)價(jià)標(biāo)準(zhǔn)Sheet3Analysisandevaluationstandard除霜模式面積標(biāo)準(zhǔn)A區(qū)速度>2m/s面積Azonevelocity>2m/sarea≥80%*A區(qū)面積≥80%*AzoneareaB區(qū)速度>1m/s面積Bzonevelocity>1m/sarea≥95%*B區(qū)面積≥95%*BzoneareaL區(qū)速度>1.5m/s面積Lzonevelocity>1.5m/sarea≥100%*L區(qū)面積≥100%*LzoneareaR區(qū)速度>1.5m/s面積Rzonevelocity>1.5m/sarea≥100%*R區(qū)面積≥100%*Rzonearea風(fēng)量分配Massflowdistribution8%～12%:38%～42%:38%～42%:8%～12%壓力損失Pressureloss壓損需滿足HVAC分解目標(biāo)值分析要求ANALYSISREQUIREMENTS求解器設(shè)置CalculatorSetting各求方程的差分格式要求使用默認(rèn)值（二階迎風(fēng)格式）。如果遇到計(jì)算發(fā)散或者不收斂，可以嘗試調(diào)小各控制方程的松弛因子，或者降低差分格式級(jí)別。待收斂性變好后，差分格式需要改為默認(rèn)值再計(jì)算。Thedifferenceformatofcontrolequationsshouldkeepthedefaultvalue(secondup-windformat).Ifthecomputingconvergenceisbad,trytodecreasetherelaxfactorsforthecontrolequationsortodegradethelevelofdifferenceformat.Whentheconvergencebecomegood,changethedifferenceformattodefaultvalue.收斂準(zhǔn)則ConvergeRule計(jì)算收斂至少需要滿足以下兩點(diǎn)要求：a)保證計(jì)算步數(shù)（MaximumSteps）不少于3000步；b)Cd值保持穩(wěn)定（Cd在變化量小于0.001的周期波動(dòng)超過(guò)1000步可視為穩(wěn)定）。Computingconvergenceshouldmeetthetwopointsbelow:Makesurethemaximumstepsnotlessthan3000;MakesuretheCdvaluetobestable(whenthestepsinwhichthedifferenceofCdislessthan0.001exceed1000canbestable.)結(jié)果RESULT降溫曲線分析除霜除霧性能主要從前擋和側(cè)窗近壁氣流速度分布情況直觀反應(yīng)，因此需重點(diǎn)關(guān)注這兩個(gè)量。表4中所列為分析主要關(guān)注項(xiàng)，流線分析、前擋速度分布、側(cè)窗速度分布和風(fēng)量分配。Thedefrostanddefogperformanceisrepresentedbythefrontwindshieldandsidewindownear-wallairflowvelocitydistributions,sowemustfocusonthesetwoitems.Thesheet4listedisthemainfocusingitems,streamlines,frontwindshieldvelocity,sidewindowvelocityandairflowmassflowratedistribution.表4主要分析關(guān)注項(xiàng)Shee4Themainanalysisfocusingitems序號(hào)NO.分析關(guān)注項(xiàng)Focusingitems序號(hào)NO.分析關(guān)注項(xiàng)Focusingitems1前擋速度分布Frontwindshieldvelocitydistributions3管道壓力損失Pipelinespressureloss2側(cè)窗速度分布Sidewindowvelocitydistributions4管道風(fēng)量分配Pipelinesairflowmassflowdist