Multi-Objective Aerodynamic Shape Optimization of Wide-Mach-Number-Range Airfoil

Hypersonic vehicle is developing towards wider speed range, wider airspace range and longer flight range. Therefore, besides the performance at hypersonic cruise, it must also take into account the sub-transonic and supersonic characteristics in the design of wide-Mach-number-range hypersonic aircraft. In this paper, the flow mechanism of thin airfoil in different speed ranges was analyzed, and the design criteria for increasing lift and reducing drag of airfoil in different speed ranges was summarized. Then, the design optimization of wide-Mach-number-range airfoil was carried out by using RANS equation flow solver and surrogate optimization algorithm based on Kriging model. Firstly, using NACA64A-204 airfoil as the baseline, a new airfoil with improved wide-speed performance was obtained by the linear weighting method. Considering the aerodynamic characteristics of sub-transonic and hypersonic flows, the airfoil was designed after multi-round optimization. Then, taking the optimized new airfoil as the original airfoil, multi-objective optimization design was carried out, and the Pareto optimal solution set of two and three objectives for wide-Mach-number range airfoil was obtained.