Study On Aerodynamic Characteristics Of Vertical Axis Wind Turbine With The Curved Plate Adding At Blade Trailing Edge

Wind energy is inexhaustible,which is one of the clean and unpolluted renewable energy.And it has been widely concerned all over the world.Meanwhile,the wind power is the main form of wind energy utilization,and the wind turbine is a vital equipment to convert wind energy into mechanical energy.Vertical axis wind turbine can accept any direction of the wind without the need to install the wind device,generators and transmission chain,which is easy to maintain on the ground and so on.Straight-bladed Vertical Axis Wind Turbine(SB-VAWT)is a typical small wind turbine,in rural areas,street lamps,irrigation and other aspects of irrigation has an important role.However,the Aerodynamic performance of the SB-VAWT is lower than the Horizontal axis wind turbine and it is need to do further improvement.In this study,a curved plate mounted on the trailing edge of the SB-VAWT was designed.The curved plate was used to change the pressure field and the distribution of vortex on the blade surface,improve the torque of the blade to do the work and reduce the vortex loss which is near the blade,to improve the aerodynamic performance of the wind turbine.The three kinds of NACA series wind turbine with thin and thick blade as the control,respectively,different length of curved plate was added to the thin and thick edge of the blade to study the variation of the performance of wind turbine.Based on the RNG k-? turbulence model,the influence of the length of curved plate on the output performance of the wind turbine is analyzed under low speed ratio by using the numerical simulation method,and the wind tunnel test is carried out.Therefore,the main contents of this paper include the following three aspects:(1)The influence of curved plate on the dynamic aerodynamic characteristics of the wind turbine is studied.The output torque and output power of the wind turbine are calculated by numerical simulation method when curved plate is or not exist,and the effect of curved plate length on output performance is analyzed.The optimized curved plate structure of the wind turbine and the original wind turbine are processed and the wind tunnel test is carried out.The dynamic aerodynamic characteristics of the wind turbine are compared under different wind speed conditions.(2)The influence of curved plate on the flow field around the blade is studied,Calculate the change of the torque coefficient with the rotation angle in a cycle when the wind turbine is running.And the flow field under typical rotation angle is analyzed,and the mechanism of the change of the output torque is discussed.(3)The influence on the static starting characteristic of the wind turbine with curved plate is studied.The influence of the presence or absence of curved plate on the starting torque of the wind turbine at different rotation angles is analyzed by numerical simulation.At the same time,the wind tunnel test is carried out and the flow field is analyzed.The following conclusions are drawn through the research and analysis:(1)A kind of blade with appropriate curved plate adding at its trailing edge under low speed ratio can improve the output performance of wind turbine.The length of the bending plate is appropriate to the chord length of the airfoil.Under the same conditions,the addition of curved plates to thick wing blades improved significantly compared to the characteristics of wind turbines on thin wing blades.(2)The trailing edge of the blade can improve the output performance of the wind turbine.When the rotation angle is between 0 and 120 degrees,the effect of no curved plate on the starting torque of the wind turbine is the same.But when the rotation angle is between 120 and 180 degrees,the starting torque of the curved plate wind turbine is obviously increased,and the effect of the curved plate eliminates the reverse torque.At the same time,the starting performance of the thick curved plate is improved obviously.(3)According to the experiment of the NACA0024 wind turbine with or without curved plate,It can be concluded that the blade trailing edge with curved plate can improve the stable speed of the wind turbine.When the wind speed is 10m/s,the speed of the wind turbine can be increased by 245r/min.(4)The pressure distribution of the upper and lower surfaces of the blade and the flow of the fluid can be changed under the certain rotation angle by adding the curved plate at the trailing edge of the blade.At the same time,the aerodynamic characteristics of the rotating angle are improved,and the performance of the whole wind turbine is improved.In this study,the validity of the curved plate was verified by numerical simulation and wind tunnel test,Combined with the flow field analysis of the curved plate to enhance the performance of wind turbine mechanism.Which provides a new method for improving the performance of wind turbine by changing the structure of the blade itself.