Analytical mechanisms for heat flux reduction on a V-shaped blunt leading edge

A V-shaped blunt leading edge(VSBLE) at the lips of three-dimensional inward-turning inlets often generates complex shock interactions and severe aerothermal loads. To date, few heat flux reduction schemes have been devised based on the generation principle of the heat flux peaks on the VSBLE. Employing a synergistic approach of theoretical analysis and numerical simulation, it is determined that the maximum pressure jump (pmax/p∞) provided by the near-wall secondary shock interaction structure significantly influences the outermost heat flux peak (qpeak1) and exhibits a strong correlation with the deflection angle (θEF) of the upstream flow. Consequently, we design a heat flux reduction model incorporating an expansion corner (EC) to validate this finding. The simulation results demonstrated a 54.23% reduction in qpeak1 under the influence of the expansion fan generated by the EC at Mach 6, although the remaining heat flux peaks, qpeak2 and qpeak3, experience some deterioration. After conducting a comparative analysis and modeling the causes of deterioration, we propose an improved model by designing the crotch centerline. This improved model consistently demonstrated excellent performance in reducing the maximum heat flux peak and preventing the deterioration of the other heat flux peaks at Mach 6-12. Additionally, correlations between qpeak1 and pmax/p∞, as well as between qpeak1 and θEF are established. This paper presents an investigation into the key factors affecting the heat flux peaks on the VSBLE and proposes a model capable of ensuring a stable reduction in the maximum heat flux of over 40% under a wide range of Mach numbers.