Aerodynamic Design Of High-Lift Devices For A Large-Scale Amphibious Aircraft

An important index for evaluating large-scale amphibious aircraft is wave resistance.Small takeoff and landing speed can effectively reduce water load and improve wave resistance,which requires a set of high-lift device with excellent aerodynamic performance.It's difficult for conventional mechanical high-lift device to meet the needs of short-distance takeoff and landing,then powered-lift device comes up.In this paper,the configuration of mechanical high-lift device for large-scale waveresistant amphibious aircraft is firstly completed;then numerical simulation of two types of poweredlift device is taken to find the laws of active flow control and design the configuration of powered-lift device preliminary.Firstly,the design objective and overall plan of the high-lift device are determined,together with the layout on span-wise and chord-wise direction.In the design of two-dimensional configuration,a type of four-element airfoil configuration is designed.Relying on CFD numerical simulation,the parameters of multi-element airfoil slot of takeoff and landing configuration were calculated and optimized,and the optimal values are selected.Based on the two-dimensional multi-element airfoil,several station profiles are selected from the cruise configuration to complete the three-dimensional high-lift device.On the basis of mechanical high-lift device,the flow control law of inner-blown flaps is studied.By increasing the blowing momentum coefficient,flow separation can be eliminated,super circulation effect can be produced,and lift coefficient can be increased.The position of nozzle and the deflection angle of flaps have an effect on the lift effect of different flaps configuration.Preliminary design of the configuration of the blowing flaps was carried out and verified by three-dimensional numerical simulation.The lifting effectiveness of the upper surface blowing(USB)is validated.The CFD simulated surface has a good lifting effect for simple flaps due to Kanda effect,which can effectively eliminate the flow separation.The scheme to further improve the efficiency of the increase is put forward.The mechanical lifting device designed in this paper basically meets the design requirements.The study of power lifting device and aerodynamic characteristics have broad application prospects.