Investigation of flow control methods for reducing heat flux on a V-shaped blunt leading edge under real gas effects

Complex shock interactions and severe aerothermal loads are often encountered on the lips of three-dimensional inward-turning inlets, which presents significant challenges to the performance and safety of hypersonic flight vehicles. However, there have been few investigations on reducing the heat flux of the lips, especially when considering real gas effects. It is, therefore, necessary to investigate flow control methods that are suitable for the lips under real gas effects. Three flow control methods are implemented in this work—a passive method with the shock control bump and stagnation bulge, an active method with counterflow jet, and a combined method. The lip is simplified as a V-shaped blunt leading edge to eliminate the influence of other structures. Numerical simulations are performed at freestream Mach numbers ranging from 6.0 to 12.0. The principles and abilities of different flow control methods for reducing heat flux are compared and analyzed. Although the passive and active methods can reduce the heat flux by more than 40% at low Mach numbers, they have an apparent deficiency under strong real gas effects at high Mach numbers. Moreover, the active method causes new heat flux peaks near the nozzle and at the reattachment position of the flow separation zone. Therefore, a combined method is proposed for further reducing the heat flux. By coupling the passive and active methods, the combined method can reduce the heat flux by nearly 60%. In general, the flow control methods investigated in this work can achieve satisfactory heat flux reduction abilities.