Rapid prediction method for equivalent thermal conductivity of aerogel nano-porous composite thermal insulation material in complex use environment

Abstract

The invention discloses a rapid prediction method for the equivalent thermal conductivity of an aerogel nano-porous composite thermal insulation material in a complex use environment. According to theinvention, an expandable calculation object basic parameter database is established and an aerogel nano-porous composite thermal insulation material is divided into a nano-scale structure and a multi-scale typical structure of a micro-scale structure according to different internal structure characteristic scales of the material. Firstly, the equivalent heat conductivity of the nano-scale structure in a dry state is obtained through calculation. Meanwhile, for the material moisture absorption characteristic caused by environmental humidity in a complex use environment, a moisture content-considered fractal cross ball rod-non-uniform water film equivalent structure model is established. For a micron-scale structure, on the basis of an equivalent heat conductivity calculation result of a nano-scale typical structure, the theoretical prediction of multi-scale heat transfer and equivalent heat conductivity of the aerogel nano-porous composite heat insulation material is realized. The method can effectively realize accurate prediction of the equivalent thermal conductivity of the aerogel nano-porous composite thermal insulation material.

Description

technical field [0001] The invention belongs to the technical field of research on thermophysical parameters of novel airgel-based composite materials, and in particular relates to a rapid prediction method for equivalent thermal conductivity of airgel-based nanoporous composite thermal insulation materials in complex use environments. Background technique [0002] Since the beginning of the 21st century, the rapid development of high-tech has increasingly high requirements for high-performance materials, especially the development of high-tech such as aviation, aerospace and space technology has continuously put forward new requirements for heat insulation materials. However, many traditional thermal insulation materials are no longer suitable for the requirements of these fields. Therefore, the use of nanotechnology to develop new super insulation materials and multifunctional composite insulation materials has become the main trend in the development of insulation materia...

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Problems solved by technology

[0006] The traditional calculation model of airgel material equivalent thermal conductivity based on empirical correlation, or based on regular structural unit model has narrow application range, low prediction accuracy, and the gap between the factors that affect the equivalent thermal conductivity of the material. Mechanistically weak

The traditional theoretical model of moisture-containing thermal conductivity of porous media cannot accurately predict the equivalent thermal conductivity of airgel materials in a moisture-containing state.

In the application of airgel thermal insulation materials to actual thermal protection systems, a series of problems such as large thermal conductivity prediction deviations and material system design failures have emerged.

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