An experimental investigation on performance of transpiration cooling with liquid water through C/SiC porous ceramic

Abstract Transpiration cooling thermal protection system has a potential application in hypersonic vehicles subjected to severe aerodynamic heating. This paper presents an oxyacetylene flame test to investigate the effect of gravity of water on transpiration cooling using C/SiC porous ceramic with liquid water and the change of capillary force in this transpiration cooling. Gravity of water affects the temperature difference between the temperatures at the top and bottom on the surface of the sample, and the pressure difference of water inside the sample represents capillary force. The experimental results indicate that the temperature difference firstly increases and then decreases with the increasing of heat flux. And temperature difference on the surface of the sample with lower porosity reaches the peak value under lower heat flux. The pressure difference of water inside the sample before and during the test rapidly increases under the low heat flux, and then gradually becomes steady when heat flow exceeds 1.7 MW/m2. Besides, there is a larger pressure difference inside the sample with lower porosity. This work can provide a useful reference for the design of the transpiration cooling thermal protection systems in hypersonic vehicles.