关键词: 再入, 气动热, 烧蚀, Landau变换, 有限差分法

Abstract: To predict the coupled response of ablation and transient temperature in the ablation thermal protection system of reentry vehicles, an integrated computing method is proposed to provide the dynamic response prediction basis for the design of ablation thermal protection of reentry vehicles, including aerodynamic heat, ablative recession and transient temperature responses. The method adopts the Sutton-Graves and Tauber-Sutton theory to calculate the convection heat flux and radiation heat flux of the stagnation-point. Through the surface energy balance, an ablation model of high precision is integrated. The Landau transformation is introduced to simplify the node removal process caused by surface ablative recession, meanwhile ensuring the space discrete precision. The transient heat conduction equation is solved by the finite difference method, obtaining the heat environment, ablation process and temperature response for the ablative thermal protection system. The applicability of the proposed method to different material systems is verified by comparison of two simulation examples: the atmospheric reentry process of carbon-carbon blunt body, and the Phenolic Impregnated Carbon Ablator(PICA) ablative materials arc wind tunnel simulation. The calculation results show good agreement with the classical thermal equilibrium integral method, with an error smaller than 7%. However, for low-density materials (such as PICA materials whose ablative properties are highly sensitive to pressure), the prediction deviation increases with the increase of heat flux and pressure. The proposed method realizes integrated calculation of aerodynamic heat, ablation and transient temperature response in the coupling process, and fast calculation on the premise of accuracy ensurance, thereby providing a basis for the design of ablative heat protection of reentry vehicles.

Key words: reentry, aerodynamic heating, ablation, Landau transformation, finite difference method