Thermal Performance Assessment of Tungsten Based Magneto-Resistive Heat Switch for Space Application

Abstract

Heat switches are generally used for regulating heat flow. These heat switches are categorized as mechanical and magneto-resistive heat switches. Among these, a magneto-resistive heat switch (MRHS) is used for controlling the heat flow at a very low temperature of below 10 K. Because of this advantage, it is implemented in space applications for controlling heat flow across thermally conductive material. Therefore, in the present study, by choosing MRHS, an analytical investigation is carried out for assessing the thermal performance at a very low temperature of below 10 K. Here, tungsten is used as a magneto-resistive material (MRM). Initially, an analytical model is developed for evaluating the thermal performance of MRHS. The created model was then evaluated using experimental data from the literature by selecting thermal conductivity, thermal conductance, and switching ratio as performance characteristics. From the validation analysis, it is found that the developed model has a reasonable agreement with experimental data and observed a maximum allowable error of 8.3%. Later, the developed model has been used for investigating the performance of MRHS. The inlet parameters chosen for the performance evaluation are magnetic field (MF) and MRM temperature. By observing the numerical results obtained based on the developed numerical model, it is found that for a given MRM temperature of 5 K and by varying the MF from 0.1 T–2 T, the thermal conductance increases linearly by 150%, the thermal conductivity decreases logarithmically by 97%, and switching ratio increases logarithmically by 99%, respectively. Further, it is realized that the developed model procedure can be adopted for assessing the thermal performance of different heat switches that are used for space applications