Shape Optimization Of Adaptive Leading-edge For Space Shuttle Airfoil

The Space Shuttle experience great changes of velocity and environment during its reentry flight in air,so the airfoil design should meet the various complicated requirements. The concept of adaptive wing can satisfy such the requirements. In this paper, the focus is on the design of the airfoil, not on its structure and control system. The aim is to get an airfoil which can meet the thermal requirements in hypersonic flight, and aero-dynamical requirements under the subsonic landing condition.Firstly, airfoil is parameterized by the analytical function linear perturbation method, and the modified Hicks-Henne type function is applied to change the shape of leading-edge. The flow field under typical re-entry orbit for baseline airfoil is analyzed by finite volume method. Therefore, operating conditions for optimization in hypersonic flight and in subsonic landing situation are determined. Subsequently, Latin hypercube method is adopted to produce 150 sample airfoils for both operating conditions, and stagnation heat flux and aerodynamic coefficients of sample airfoils are analyzed by CFD-Fastran code to construct the response surface surrogate model, respectively. The multi-island genetic algorithm is applied to optimize the surrogate model for the optimal airfoil. The design variables are the coefficients of perturbation terms in the airfoil function, and the optimization objectives are heat flux of stagnation and lift-to-drag ratio, respectively.On hypersonic flight condition, the relationship between heat flux of stagnation and velocity is given in this paper. On landing condition, the aerodynamic coefficients and pressure distribution curve of optimal airfoil is also calculated.