Abstract: The two major heat short problems of gap radiation and brackets in metallic thermal protection system (TPS) are studied in this article. Numerical analysis is carried out to evaluate the influence of gap width and emissivity on heat shorts. A series of steady heat transfer experiments on TPS sample and array is completed, and the influence of heat shorts on performance of TPS is studied quantificationally. The experimental results show that heat shorts occur at the site of brackets, and the resulting temperature difference is as high as 50 K. When the temperature is lower than 773 K, the temperature difference induced by gap heat transfer increases linearly as the gap width becomes larger. When the temperature is higher than 773 K, however, the radiation phenomenon becomes a dominant factor influencing the mechanisms of heat transfer as the gap width is larger than 3 mm. And the temperature difference does not change linearly as the gap width increases. The numerical and experimental methods presented in this study can provide some reference for the design and analysis of metallic TPS.

Key words: thermal insulating materials, heat radiation, heat shorts, gap width, TPS array