Transient inverse heat conduction analysis of atmospheric reentry vehicle using FEM

Thermal analysis is required in the design of the structure of atmospheric reentry vehicles, which are subjected to severe aerodynamic heating. However, prediction of aerodynamic heating is difficult owing to highly complex physical phenomena. Inverse heat conduction analysis, the methodology to estimate heat flux on boundaries and entire temperature distribution from limited number of temperature measurement, is expected to solve this problem and to contribute to improving structural integrity. Present study develops computational method of transient inverse heat conduction analysis using finite element method and pseudo-inverse matrix. The developed inverse analysis code is applied to a reentry vehicle in order to examine the present method and to discuss the computational stability and regularization methods. Sequential function specification (SFS) method and rank reduction are employed to improve the accuracy and stability of the inverse analysis. The results of the numerical simulation reveal that the present method works effectively in solving inverse problem stably by using the combination of SFS method and rank reduction. Especially, the rank reduction is quite efficient at regularization. SFS method requires proper number of future time steps.