Estimation Of Aerothermal Parameters For Variable Geometry Heat Conduction Problem

Inverse Heat Conduction Problem(IHCP), which is widely applied in spaceflight,nuclear physics and metallurgy, such as the determination of the surface heat flux andthermal conductivities of material, transition locations and so on, is a typical InverseHeat Conduction Problem (IHCP). More and more institute get into this research field,but up to now, almost all the works carried out aim at identification problems forsteady-state geometry heat conduction problem, few for variable geometry, however,the shape of the heat transfer region may change with time and sometimes evenunknown. So extending the techniques on steady-state geometry to variable geometryhas great importance in both scientific research and engineering field. In this thesis,the special identification algorithm of aerothermal parameters for variable geometryheat conduction problem will be given.In the preface of the thesis, we introduced the background of estimation ofaerothermal parameter, several classical examples and the main research contents.Dependable thermal protection system is the foundation of the development of newhypersonic vehicle while estimation of aerothermal parameters is an important meansof thermal protection system’s elaborate design.In the second chapter, we introduce the numerical algorithm on variable domainused in this thesis, Finite Control Volume Method and Finite Element method, andcheck their accuracy by comparing with heat conduction problem with analyticalsolution.In the third chapter, we introduce the two most important estimation method usedin this thesis, Sequential Function Specification Method and Conjugated GradientMethod, and then give the identification algorithm for identifying surface heat flux ofvariable geometry heat conduction problem based on them. We check the algorithm’saccuracy and stability by simulation experiment, and illustrate factors which mayinfluence the estimated results.In the fourth chapter, we give the estimation algorithm for identifying thevariable shape of the heat conduction region from external measurements, especiallythe2D irregular boundary configuration. In the end we checked its accuracy andstability by simulation experiment.In the fifth chapter, estimation algorithm for identifying surface heat flux whenablation (include charring and pyrolysis process) of material happen is given.According to the heat conduction model with pyrolysis interface chosen in thischapter, identification algorithm is given and checked by simulation experiment. At the last chapter, a review about the work in the thesis was made, the shortageof the work and the direction about the future research are presented.