Reusable Launch Vehicle Thermal Protection System Performance Study

The unique function of the thermal protection system(TPS) is to maintain the vehicle structural temperature within allowable limit during re-entry aerodynamic heating, which is critical to a new generation of reusable launch vehicles(RLV). Some countries, such as USA, Russia, France etc, have fruitful research experience and are developing more excellent TPS. But in our country, all aspects of research of RLV are just beginning. For TPS, we have neither engineering experience nor systemic study base. As one part of reusable lunch vehicle TPS researches and the beginning of systemic study in our country, the purpose of this thesis is to present a methodology to predict the transient temperature response and size TPS with high-fidelityFor RLV, the weight of the TPS is typically comparable to the payload weight. Therefore, any improvement of TPS sizing calculations, which leads to an actual reduction in TPS weight, has a significant cost and feasibility impact on RLV design. TPS design involves proper selecting and locating a great number of TPS materials, which have complex configuration and heat transfer mechanism. With these characteristics, a heat transfer methodology is introduced in the thesis. The methodology made the heat transfer analysis of TPS in two different analysis processes, which are bulky thermal protection system sizing and typical structures heat transfer. General TPS thermal model and typical structure thermal models are investigated respectively to realize the TPS sizing and meso-structure parameters design of typical structures.General TPS thermal model is studied in detail. According to general TPS thermal model function in the TPS thermal analysis, an one-dimensional transient heat transfer model is proposed on the assumption that its structure/material in TPS is homogeneous and ignores its meso-structure character. General TPS thermal model only deals with the effective properties of its structure. While, mass model for every TPS is given. Then the numerical analysis is developed using finite-difference method. Through particular formula analysis, an one-dimensional, non-linear, full implicit, transient finite-difference model is proposed. General TPS thermal model meets the requirement of analysis in extensive level and makes overall transient analysis and TPS sizingpossible.In the thesis, the TPS is described as construction of some typical structures, and TPS properties intensely depend on typical structure properties. Through comparing TPS with each other, which are widely used or have enormous potential, four typical structures are summarized, that is, rigid ceramic tile/flexible ceramic blanket, inner multiplayer insulation, metal mutil-wall structure and metal honeycomb panel. Base on investigating of heat transfer mechanism of each typical structure, heat transfer process is simplified into one or two dimensional analytical model respectively. Finite difference or finite element model is applied to different typical structure from its character. Some important parameters that influence the heat-proof properties of each typical structure are well investigated by using the numerical model, which will be helpful to direct parameter-selection and TPS properties improvement.In the last part, TPS scenario optimal design is discussed. Methodology and numerical procedure developed at this thesis is used to investigate optimum design of an envisaged two-stage-to-orbit launch vehicle thermal protection system. Under the circumference of the aerodynamic heating given by engineering, an optimal TPS material layout is proposed on the vehicle surface. Taking the vehicle as reference, optimal design of aerodynamic heating and inner structural material are examined to reduce TPS mass as possible.