RESUMO

The objectives of this work are to present and compare theoretical models for predicting the overall thermal resistance of a passive bimetallic heat switch. The heat switch was developed to reduce the thermal load coming from the satellite structure to cryogenic sensors. The overall thermal resistance of the heat switch is a function of its mean temperature level. A brief description of the heat switch and of its working principle is presented. Two analytical two-dimensional models, one analytical one-dimensional model, and one numerical two-dimensional model are presented. The analytical two-dimensional models were developed using a novel technique to solve a two-dimensional boundary-value problem with coupled domains. This new technique proved to be quite accurate when compared with the numerical two-dimensional simulation of the heat switch temperature field. The one-dimensional model demonstrated that the heat flow in the heat switch is one-dimensional over almost the full range of operation of the heat switch.