Typical Cover Heat-resistant Structural Performance Analysis And Optimization Design

With the rapid development of transonic and hypersonic technology, the space vehicle was forced to face severe aerodynamic heating. As one of the critical technologies, the function of the thermal protection system was to control the heat energy and maintain the vehicle structure within acceptable limits during aerodynamic heating. The mass and sizing of thermal protection system affected the reliability and mobility of vehicle directly.A study was performed to develop an understanding of the thermal analysis and performance optimization of typical passive thermal protection system. First, several background information was reviewed and applied to the development of thermal protection system. General approaches to thermal protection were categorized and critiqued. The over arrangement of thermal protection system on different vehicles were also reviewed. A current typical rigid external thermal protection system concept which was consists of a rigid external shell panel and inner lightweight thermal insulation was presented and systematically analyzed. Multi-layer insulation and functionally graded insulation were two insulation candidates being considered for use in the thermal protection system on space vehicles. The basic heat transfer mechanisms in porous media was considered and discussed. Heat transfer through insulations was simultaneous by solid conduction, gas conduction and radiation. Convection in porous media at high temperatures can be neglected. The combined radiation and conduction heat transfer through thermal insulations was modeled numerically using finite difference method and finite element approach. Typical reentry temperature and pressure were used for calculation as boundary and environment conditions. A large number of relevant factors that influence the thermal analysis and thermal performance of multi-layer insulation were identified and quantified. The research showed that for four foils multi-layer insulation locating the foils 3mm away from the hot boundary and 12mm reflective foil spacing is the optimum design which had the best performance. At the last part of the dissertation, the use of functionally graded insulation was investigated. Detailed comparisons were performed to predict the thermal performance of two layers functionally graded insulation with varied density and geometry. The functionally graded insulation was optimized to minimize the maximum structure temperature and the mass separately...