Method for measuring anisotropic material heat conductivity based on small-plane heat source

Abstract

The invention discloses a method for measuring anisotropic material heat conductivity based on a small-plane heat source. The method comprises the following steps: building a three-dimensional heat transfer model of a measured sample in a right-angle coordinate system in a special form under the action of thermal interference; obtaining an analytical solution of temperature change in anisotropic material in a time domain by adopting Laplace transformation, variables separation, transcendental equation solving and inverse Laplace transformation methods; through sensitivity calculation, analyzing linear correlation of sensitivity coefficients of normal heat conductivity and tangential heat conductivity and the effects of parameters on temperature change; building an experiment measurement system, and collecting transient response data of the temperature; and simultaneously determining the normal heat conductivity and the tangential heat conductivity of the measured anisotropic material by an improved Gauss Newton parameter estimation method. The method has the advantages that the transient measurement method which is convenient to implement, fast in measurement and wide in application range and adopts simple steps is provided, and the normal heat conductivity and the tangential heat conductivity of the rectangular anisotropic material can be obtained by once measurement.

Description

technical field [0001] The invention belongs to the technical field of thermal physical property measurement of materials, and in particular provides a new measurement method for simultaneously obtaining the thermal conductivity in the orthogonal direction through one measurement. By measuring the temperature change of a point in the measured sample, the anisotropic material Normal thermal conductivity and tangential thermal conductivity. Background technique [0002] In recent years, with the rapid development of high-tech and industrial applications, the development and application of anisotropic composite materials has become a research hotspot. Composite materials with anisotropic characteristics are not only used in cutting-edge fields such as aerospace and nuclear energy utilization life sciences, but also in various industries such as construction, electronic machinery, medical sports, etc. due to their advantages such as high strength, high toughness, and good therma...

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Problems solved by technology

However, these measurement models still have certain deficiencies and limitations in the actual implementation.

If some methods need to give the sample to be tested two thermal interference signals perpendicular to and parallel to the fiber direction at the same time, and keep the boundaries of other samples to meet the adiabatic conditions, it is difficult to implement in the experiment; some methods are difficult to solve in the parameter solution Using numerical calculations or simplified analytical solutions has low precision; some methods need to re-do physical modeling and meshing for different test samples, or use two methods, which is cumbersome and reduces In other methods, the measured material needs to be prepared into a cylindrical shape, which brings difficulties and challenges to the development and preparation of new or special-purpose materials, and puts forward many restrictions on actual measurement.

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