Parametric identification of thermophysical characteristics of heat-protective decaying materials

Abstract

The paper presents a method of identifying the thermophysical properties of heat-protective materials of complex multi-component composition used in structures to meet the specified requirements for their resistance to external temperature influence. The research is dedicated to the study of a thermal barrier coating material containing chemically active components that enter into a chemical decomposition process, accompanied by the heat absorption. The equivalent specific heat capacity of the material reflects its thermophysical properties, taking into account the endothermic reaction. The equivalent specific heat capacity is identified by solving the inverse heat conduction problem using the results of temperature measurement in a multi-layer structure element during the thermophysical experiment. Regularization of this incorrect inverse problem is performed when it is transformed into a mini-max parametric problem of semi-infinite optimization. The results of differential thermal analysis and known qualitative laws of endothermic reactions make it possible to narrow the set of feasible solutions to the level of a compact set of piecewise continuous functions of a special structure, which provides a reduction to the parametric optimization problem. The minimax problem is solved by an alternance optimization method. The results obtained confirm the effectiveness of the proposed method for solving applied problems.