Effect of structural factors on maximum aerodynamic heat flux of strut leading surface

For the high enthalpy of the incoming flow, thermal protection is a very important issue for hypersonic vehicles. Strut is a commonly used intrusive fuel injector, and a focus in thermal protection of scramjet engine. In order to reduce the cooling requirement of strut by appropriate structure design, numerical simulation has been carried out to study the effect of structure on the maximum aerodynamic heat flux on strut surface. The considered strut structural factors in this work consist of sweep angle, tip gap, and leading edge transition arc radius. The results show a decreasing trend of both maximum and area-weighted average aerodynamic heat flux on strut leading surface when the strut sweep angle became large. Relative to the case of straight strut, the maximum aerodynamic heat flux reduced 70-80% in the case with a sweep angle of 75°. Influence analysis of strut height present that it is favorable for reducing maximum aerodynamic heat flux by leaving a tip gap between the tip surface of a swept backward strut and the combustor wall opposite. Though the strut leading edge is much sharp with transition arc radius less than 1 mm, blunter strut pushes the attached bow shock farther away from leading surface, and decreases the maximum heat transfer flux on the leading surface. However, the decreasing of heat flux is less as the bluntness radius is larger, and the heat flux reduces little when the bluntness radius is larger than 0.5 mm. Moreover, the blunt leading goes against drag and flow losses reduction.