Study on helium impingement cooling for a sharp leading edge subject to aerodynamic heating

This paper presents numerical studies on a typical actively-cooled thermal protection system (TPS) which turns out to be a potential candidate for the leading edge thermal management. The leading edge is cooled by the impingement jet of gaseous helium. The external aerodynamic heating and radiation, the heat conduction in solid wall, and the internal impingement cooling are coupled in a unified computational fluid dynamics system by using a quasi-coupling method. The thermal-hydraulic performance of internal impingement cooling is particularly highlighted. Four metal alloys are tested in order to find out the impact of the material property on the TPS's cooling performance. Results show that the reduction of leading edge temperature is remarkable with the impingement cooling scheme and the maximum temperature can be controlled far below the materials' melting point. However, the thermal stress does not significant decrease and is still a barrier for the application of the actively-cooled TPS. The operation limits of various materials are demonstrated, which may benefit to the future material selection work. Besides, the coolant flow rate requirements for safely operating the TPS under various flight conditions are ascertained.