文档介绍：REACTINGFLOWENVIRONMENTSBRANCHELORETDECOUPLINGFLOW&MATERIALRESPONSE解耦流及材料反应•putationsshouldguidethischoice初始设计阶段未选择防热系统材料–计算应引导至此选择•Assumethatthesurfaceisnon-conductingandcanonlyre-radiate–adiabaticbackwallassumption假设表面无传导性,只有再辐射性–隔热后墙假设•binationofatomsreachingit–conservativeassumptionbecausemaximumheatreleasecanbeexpected假设表面促使到达表面的原子完全重组–保守假设从而得出最大散热•Aerothermalanalysiscannowbeperformedwithasteadyflowassumptionatanytrajectorypoint–timediscretization气动热分析只能在稳定流场假设下的任意轨道点进行–时间离散化•putations–putationsrequired时间离散化不太适用于CFD计算–需要对大量数据进行计算•uracy–engineeringmethodsaremuchquicker需要使用合适精准度的工程学方法补充CFD计算–工程学方法更为快速May11,2004DP-8REACTINGFLOWENVIRONMENTSBRANCHELORETABOUTTHISPRESENTATION关于此次演示•binationofCFDandengineeringmethodologyindefiningaerothermalenvironmentsforTPSdesign演示为防热设计所定义的气动热环境下的CFD与工程学方法的结合•AssumesEarthatmosphericflight–flowmediumconsistsofN2,O2,&products假设地球大气层飞行–气场至少包含氮气、氧气及其化合物•Doesnotcalloutmaterialchoicesorsizing不涉及材料选择及大小•UsesX-33flightvehicleasacasestudy使用X-33飞行器作为案例研究•ountofvariousapproaches此演示非多种方法的综合预计•Thepresentationisafocusedone–drawnontheexperienceofasmallteamatNASAAmesResearchCenter此次演示为一次演示–由NASA阿姆斯研究中心一个小组经验绘出May11,2004DP-9REACTINGFLOWENVIRONMENTSBRANCHELORETREQUIREMENTS–CONFIGURATION要求–结构•Sincein-depthconductionisneglected,onlytheoutersurface(outermoldlineorOML)definitionisrequired由于已忽略深度传导性问题,此处只要求对外表(外模线,又称OML)做出定义•ConfigurationisusuallyavailableinsomeCADformat在一些CAD公式中可得出结构•TranslationofCADformatsisanissue翻译CAD公式是一个问题•CADfilecontainslotmoredetailsthanarenecessaryCAD资料包含远超过所需的数据•OMLhastobeextractedfromtheCADfileOML需要从CAD资料中分离•OMLhastobe“watertight”foruseingridgeneration应用于网格生成的OML应该“天衣无缝”•CADfilewillrequiresomecleanupCAD资料将需要整理•Stitchingsurfacestogether将表面固定到一起•Closinggaps密封空隙•Makerequireadditionalapproximationsorsimplifications进行必要的概算或简化May11,2004DP-10REACTINGFLOWENVIRONMENTSBRANCHELORETREQUIREMENTS–TRAJECTORY要求–轨道•ParametersrequiredforCFDsimulationsareCFD模拟需要的参数为•Flightspeed(orfreestreamMachnumber)飞行速度(未扰动流马赫数)•Freestreamtemperature未扰动流温度•Frees