Morphing Winglet Design And Optimization For Civil Airplane

As an important design for reducing flight drag, winglet is widely used in civil aircraft.Winglet improves the aerodynamic performance of the aircraft by weakening the strength of wingtip vortex. The traditional winglets are mainly designed for cruising, while the drag reduction effect for other non-design points like take-off and landing is not obvious.Therefore, researchers have proposed the morphing winglet. Morphing winglet can change shape in real time with the flight conditions to achieve optimal aerodynamic performance of the aircraft.On the basis of winglet design information from home and abroad, the effect of winglet shape parameters on the aircraft aerodynamic performance is studied in this paper by choosing the wing of a large civil aircraft as the basic wing and using the lift-drag ratio as the assessment indicator. The study includes two parts, the single parameter optimization design and the multi-parameter optimization design. The single parameter optimization design selects the sweep angle of winglet as the optimization parameter. The wing models are established by three-dimensional graphics software. Numerical solutions of lift-drag ratio under each condition of the models are obtained by the method of Computational Fluid Dynamics(CFD). The simulation results show the relationship between winglet sweep and the aerodynamic performance of the wing model under different flight conditions. The multi-parameter optimization design selects the winglet height, the wingtip-root ratio, the camber and the sweep angle as optimization parameters. Numerical solutions of lift-drag ratio under each condition are obtained by the method of Computational Fluid Dynamics(CFD) method. The optimal combination of winglet shape parameters under each flight condition is obtained by comparing lift-drag ratio. The stepwise regression analysis of the results demonstrates that, among the four winglet parameters, the winglet height and the camber have the most significant impact on the aerodynamic performance while the root-tip ratio has the least impact.The Single parameter optimization design provides a new way of morphing winglets.The multi-parameter optimization design has instructiveness in the research direction of morphing winglets. The research method and the research results of this paper have practical value on the development and application of morphing winglets.