热防护系统多层隔热结构传热分析及性能研究

TPS multi-layer insulation thermal analysis and performance study

由外部高温合金壳板及内部多层隔热结构组成的金属热防护系统被认为将在未来重复使用运载器上大面积采用。分析了多层隔热结构内导热与辐射的复合换热问题。采用二热流近似方法分析了纤维席内的辐射热流。分析了多孔介质纤维席内气体、固体有效导热系数。并应用有限差分法建立了多层隔热结构瞬态传热数值分析模型。反射屏层数、发射率及纤维席厚度、密度是多层隔热结构重要的设计参数。详细的分析了这些参数对多层隔热结构隔热性能的影响,总结了提高多层隔热结构隔热性能的方法。

Light weight,nonloadbearing internal multiscreen insulations (IMI) is an important insulation part of metallic thermal protection systems,which have been proposed for insulating major portions of reusable launch vehicles.The combined radiation/conduction heat transfer in hightemperature multilayer insulations was investigated in the present study.A numerical thermal model was given using nonlinear,implicit,onedimensional finite difference technique.The radiation heat transfer was modeled using the twoflux approximation.Solid and gas conduction were modeled using techniques for high porosity.In present paper, important parameter such as the foil number,spacing,locating,emittance and fibrous density were analyzed.The parameter design rules are summarized,which are helpful to the optimum design of IMI for reusable launch vehicle.