Identification of thermal processes by solving inverse problems

Abstract

Research of thermophysical processes, based on the experiment, is considered the most reliable source of information about the thermal state of the object. However, since there are incompatible material costs during the experiment, mathematical modeling and identification methods are more often used to determine temperature fields, heat exchange conditions, and other thermal parameters. In view of this, it is necessary to take into account the economic factor, which is of great importance in the choice of methods and technical means to achieve the set goal. Determination of thermophysical characteristics of materials and boundary conditions by experimental methods, due to their imperfection, often cannot be an exhaustive source of information about the conditions of unambiguity. Therefore, much attention is paid to the methods of inverse problems, in which, based on the available information about the thermal and thermoelastic state inside the body, it is possible to refine the mathematical model of the phenomenon itself. The methodology of solving inverse problems makes it possible to identify the parameters of thermal systems and processes by their indirect manifestations. Whatever methods and tools the researcher uses, the results of modeling depend on the adequacy of the mathematical model, where the main importance is attached to the reliability of the applied conditions of unambiguity. Therefore, the leading role of mathematical modeling and identification in the study of thermophysical processes is characterized by increased requirements for the effectiveness of their methods and the ease of their implementation. The book has nine chapters. The first three sections are mainly of an overview nature and their material can be used as a reference. Chapter 4 is devoted to the identification of the interaction of the body with the environment, which, in particular, considers the determination of the heat flow at the boundary of the body, as well as the determination of the degree of blackness of the body surface and the temperature of the environment during heat exchange according to the Stefan-Boltzmann law. Chapter 5 examines the identification of the thermophysical characteristics of the body based on the data of a thermophysical experiment, and Chapter 6 presents methods for solving geometric inverse problems of heat conduction. Methods for solving inverse problems of thermoelasticity are considered in chapter 7. In particular, it is of interest to determine the heat exchange coefficient based on the measured displacement and use the methodology for solving the inverse problem to predict the destruction of power equipment elements. Chapter 8 describes the use of the IPMash developed by scientists. A. M. Pidgorny of the National Academy of Sciences of Ukraine spherical solar collector for thermal energy storage. The last chapter of the book presents problems of thermoaeroelasticity and the methodology of their solution. The book is the result of many years of research carried out by the employees of the Institute of Mechanical Engineering Problems named after A. M. Pidgorny National Academy of Sciences of Ukraine.