翼上螺旋桨构型耦合气动特性及翼型优化设计

This paper studies the characteristics of the propeller-wing coupled flow field of the channel wing configuration. It also carries out an airfoil optimization with the aim to improve the lift efficiency at Short Takeoff and Landing (STOL) condition. By adopting the momentum source method and carrying out the real blade model CFD analysis of the propeller-wing interaction flow field, this paper first analyzes the feasibility of the momentum source method for the design. Then, to obtain a new airfoil with coupled aerodynamic features, an parameterized model with Free-Form Deformation (FFD) method is established to optimize the airfoil of the channel wing, and the changes of optimal airfoil parameters and the flow field are analyzed. In the end, the CFD analysis for three dimensional channel wing is carried out to compare and verify the two-dimensional airfoil optimization results. The results show that the Multiple Reference Frame (MRF) method cannot correctly analyze the flow field of over-the-wing propeller, while the momentum source method is more consistent with the unsteady sliding mesh method. The genetic algorithm optimization using the two-dimensional momentum source CFD method is effective. With the protection of the half-duct, the advantages of two-dimensional optimization airfoil have been effectively inherited in the three-dimensional configuration. The airfoil design for channel wing configuration should focus on the curvature variation of the wing surface. In this paper, the Coanda effect is enhanced by increasing the curvature of the airfoil near the propeller and maintaining the attached flow, which achieved aerodynamic lift-increase. The lift of the optimal channel wing increases by 22.51%, and the high pressure area is significantly reduced behind the propeller and second peaks of suction appears, while drag is still negative.