Experimental study on the thermal insulation performance of semi-transparent materials based on convection heating method

Abstract

Radiation heat transfer inside the aerogel materials belongs to medium radiation, so different heating methods have different measurement results of thermal conductivity. For aerogel materials applied in high temperature air flow environment (aerospace field), since the real boundary conditions of aerogel materials during operation can be simulated by convection heating method (CHM), the combustion-gas wind tunnel device based on two-stages atomization, two-stages combustion/mixing mode is constructed, and the performance test is conducted. The operation safety and combustion performance of the device meet the test requirements, so the thermal conductivity test of aerogel materials can be carried out. When the average temperatures are 469 K, 622 K and 763 K respectively, the effective thermal conductivity (ETC) measured by the CHM is smaller than that measured by the thermal conduction heating method (TCHM), which decreases by 2.7 %, 7.84 % and 9.23 % respectively. The CHM solves the limitations of the TCHM, so the ETC of aerogel materials measured by CHM is more valuable for the design of thermal protection system.