Abstract:

When hypersonic vehicle flies at a certain angle of attack， shock wave interaction causes banded high heat flux regions along the flow direction on the windward surface， imposing an adverse effect on the design of thermal protection systems. We investigate the aerodynamic thermal optimization of a lifting body flying at Mach number of 17 and an angle of attack of 8° at 50 km altitude. To improve the aerodynamic global optimization design framework， the continuous adjoint method is firstly adopted to analyze the first-order surface sensitivity of aerodynamic force and thermal characteristic parameters， and the Bèzier free-form deformation method for parameterization based on sensitivity analysis is then proposed. Specifically， the control lattice and design space are both adjusted using this method. To meet the aerodynamic heat protection and thermal insulation requirements of hypersonic vehicles， the single and multi-objective aerodynamic global optimization of the windward side shape is performed with the objectives of heat reduction of banded high heat flux regions on the windward side and spanwise movement of the banded regions outwards. The constraints include stagnation heat flux， effective inner volume， lift-to-drag ratio， length and width. After the single-objective optimization， the decline degree of the peak value of the heat flux on the banded region is increased by 36%， and movement of the spanwise location of banded regions is enhanced from 19.7% up to 21.6% using the proposed parameterization method. In terms of multi-objective design， the overall decrease in heat flux of the optimal solution sets is observed using the parameterization method based on sensitivity analysis， and the Pareto front shrinks and advances towards the optimum， achieving the aerodynamic and thermal refinement design of the lifting body.

Key words: lifting body, hypersonic, aerodynamic design, global optimization, aerodynamic heating, sensitivity analysis, parameterization