Transpiration Cooling Tests of Porous CMC in Hypersonic Flow

During hypersonic flight the temperatures on the vehicle can reach very high values in certain locations. A hypersonic flight vehicle needs to be designed aerodynamically efficient. That results in rather small nose and leading edge radii which drives up thermal loads due to the fact that the loads depend on the curvature radius of these elements. Therefore thermal protections is required for these elements. However, even ceramics reach their use temperature limits when e.g. the leading edge radius of a space plane is in the order of only a few centimeters. Transpiration cooling could be a means to handle the thermal loads in certain critical locations for a hypersonic flight vehicle. This paper describes the loads derived for a conceptual space plane vehicle, the SpaceLiner, and also reports on the initial tests for transpiration cooling of ceramic matrix composites in the hypersonic flow of an arc jet facility.