Study On The Aerodynamics Of The H-type Vertical Axis Wind Turbine

Vertical axis wind turbines have a huge advantage compared with traditional horizontal axis wind turbines. The vertical axis wind power technology has been in a backward position because the lack of basic theory research, and in recent years, the vertical axis wind power technology has been going back into scholars' sight with the deeper research about vertical axis wind power technology. With highly complexed flow field while VAWTs are running, it is very difficult to predict the VAWT's aerodynamic performance by theoretical methods. In this paper, Computational Fluid Dynamics, a rapidly developed method in recent years is used to predict the aerodynamic performance of the VAWT, and get the internal flow characteristic distribution of the VAWT. Summarizes the general process of using the CFD method to calculate the aerodynamic characteristic of the VAWT; 2D CFD method is applied to analyze the flow characteristic of the rotor domain when the turbine is in operation, and reveals the general regularity of the VAWT gain it's power from wind during operation; 3D CFD method is used to accurately solve the turbine's aerodynamic response; then, an experimental test is build to validate the result of CFD calculation.Based on the research of the power gain law of the H-type vertical axis wind turbine during it's operation, the variable parameter method is applied in the CFD analysis process to study the effect of key parameters of the rotor on it's power conversion and absorption, get the influence of the blade chord length, the radius of rotor and the number of blades on rotor's power conversion, and provide a basis for the VAWT's areodynamic design.Considering high negative torque will influence the rotor's power output produced by the aerodynamic drag force while the blade of the rotor is location in the back forward aera in the rotor operation process, a baffle structure is added to the rotor to reduce the negative torque and improve the rotor's aerodynamic performance. Then the CFD method is applied to study the baffle's influence on the aerodynamic performance of the wind turbine while the baffle's parameters are changing. Result shows that after adding a baffle structure in appropriate parameters, the wake flow produced by the baffle device has low wind speed and energy, which will greatly reduce the aerodynamic drag force acting on the blade located in the back forward aera of the rotor, thus the aerodynamic torque of the rotor will be improved greatly, the turbine will also operation in a better aerodynamic performance. In the research of this paper, the power coefficient of the rotor get 36% increased most, and the adding of a baffle structure provides a new idea for the development of vertical axis wind turbines.