Inverse heat transfer analysis in axisymmetric enclosure and concentric annulus

Abstract

Inverse heat transfer analyses have been applied to an axisymmetric enclosure and a concentric annulus, in which radiation heat transfer is dominant. In the former case, various inverse methods and sensitivity methods are compared in terms of their features such as computational accuracy and efficiency, and alternative procedure is established for faster, more stable and easy-to-use inverse analysis while estimating boundary conditions such as temperature and emissivity. Firstly, the hybrid genetic algorithm improved by adopting a local optimization algorithm is proposed, and applied to inverse surface radiation analysis of diagnostics and design problem. In this case, no gradient information for estimation of boundary condition is necessary. Secondly, for parameter estimation, the hybrid genetic algorithm, which is one of search-based method, is adopted as initial guess selector for gradient-based methods such as the conjugate gradient method or the finite-difference Newton method. The hybrid genetic algorithm provides initial guess values of good quality, which make gradient-based methods be able to estimate the global optimal value even in case of highly correlated between parameters. Lastly, for function estimation, the combined method of the automatic differentiation and the Broyden combined update is proposed due to their own merits such as no human effort and fast computational time. The fast calculator of sensitivity matrix is necessary because of many numbers of parameters in function estimation approach. Even though the adjoint problem with the conjugate gradient method is fast and powerful, thus, prevalent, human effort is needed for derivation of the adjoint problem from governing equation. Consequently, the proposed inverse procedure contains the Levenberg-Marquardt methods as inverse methods and the combined method of the automatic differentiation and the Broyden combined method as sensitivity method. In the latter case, the proposed inverse proce...