METHOD OF IDENTIFICATION OF THERMOPHYSICAL CHARACTERISTICS OF THERMAL INSULATION MATERIALS INTENDED FOR TEMPERATURE CONTROL OF EQUIPMENT IN ZERO GRAVITY CONDITIONS

Abstract

Background. This paper examines a sequential algorithm for identifying thermophysical characteristics, such as the thermal conductivity coefficient of the material, mass heat capacity and integral emissivity of the cryogenic thermal insulation surface for the orbital flight segment. Materials and methods. All characteristics are considered functions of temperature and are described by linear continuous basis functions. The initial data is an array of temperature measurements in the area where temperature sensors are installed, geometric parameters of the installation, and known initial boundary conditions during experimental thermal testing. The first step is to solve the “direct” problem of heating the material, after which the root-mean-square functional of the discrepancy between the theoretical and experimental temperature fields in the area where the temperature sensors are installed is compiled. Next, the problem of minimizing this functional is solved using the conjugate directions method with a preliminary selection of the descent step, based on the minimum of the target functional at the next iterations, starting from the second. Results and conclusions. When the criterion for stopping the iterative process is met, it is considered that the characteristics have been found, otherwise this sequence must be repeated a greater number of times.

Keywords

• cryogenic installation
• a liquid nitrogen
• iterative regularization
• coefficient inverse problem
• orbital flight