LM correction method for identification of heat conductivity changing along with temperature

Abstract

The invention discloses an LM correction method for identification of heat conductivity changing along with the temperature. The method comprises the following steps that input data is read from an input file; the measurement physical quantity temperature or the heat flux calculation value is obtained; an optimized objective function is calculated; whether convergence is conducted or not is checked; the identification parameter update value is obtained; an identification result is output after multi-time iteration. A traditional LM method is introduced through a complex variable derivation method, coefficients of a sensitivity matrix are accurately calculated, accordingly, high-precision identification of heat conductivity changing along with the temperature is achieved, and the precision and the stability of the traditional LM method in the process of identification of heat conductivity changing along with the temperature are improved. The complex variable derivation method is a very promising method. Compared with a traditional finite difference method, a first-order partial derivative only needs to be directly calculated, truncation errors are avoided, and the method does not depend on the space step length.

Description

technical field

[0001] The invention relates to thermal conductivity identification technology in aerospace field, iron and steel industry, chemical industry field and material preparation and characterization, in particular, a thermal conductivity identification method of new material / structure changing with temperature. Background technique

[0002] In order to meet the higher and higher Mach number requirements, it is necessary to continuously develop new low thermal conductivity insulation materials, whose thermal conductivity varies with temperature and has a nonlinear relationship. It is very difficult to determine the thermal physical parameters of thermal insulation materials with temperature changes, because: the thermal conductivity value is very small, between 0.0001 and 0.1; the temperature range is large, between 0 and nearly 2000 ° C, which needs to be determined There are many thermophysical parameters that change with temperature. Taking 0 to 1200°C as an exa...

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