Effect of radiation on the contact thermal resistance in vacuum

Abstract

The solution to most of the problems of ensuring the operating characteristics of units and assemblies of complex technical objects in a wide range of changes in temperature and mechanical loads is associated with ensuring the conditions of contacting surfaces, i.e. with the solution of the contact problem of determining the thermal and strength state of the connection of parts. This problem is also relevant to objects operated in space in a vacuum, where heat transfer between parts can occur only in contact spots (areas of direct contact of surfaces) due to thermal conductivity or due to radiation in places where there is no direct contact. Obviously, in this case, the total contact thermal resistance consists of the composition of these types of heat transfer, and largely depends on the profile and roughness of the contacting surfaces. An assessment of the effect of reemission on the value of contact thermal resistance when the temperature in the contact zone varies from 200 °C to 800 °C under vacuum conditions can allow a much more accurate prediction of the operational characteristics of the contact pair. In this paper, we compare the effect of reemission on the value of contact thermal resistance under various mechanical stresses.