Numerical Study On Aerodynamic Performance Of H-type Vertical Axis Wind Turbine

China has been vigorously advocating energy conservation and environmental protection,so it pays special attention to the use of new energy such as wind power.Traditionally,horizontal axis wind turbines are considered to be more efficient.However,as more and more scholars study the theory of vertical axis wind turbine in depth,it is found that vertical axis wind turbine has more advantages in the design and application of small and medium-sized wind turbine.It is of great significance for the future development of wind power.Because the internal flow field of the vertical axis wind turbine blade is extremely complex when it rotates,its theoretical calculation will be difficult.Therefore,the computational fluid dynamics(CFD)method is adopted in this dissertation to simulate and analyze the flow field around the blade of H-type vertical axis wind turbine when the rotor rotates.At the same time,the Fluent software is used to calculate the wind energy utilization coefficient Cp and the torque M equivalent when the wind turbine is running.Through the vertical axis wind turbine flow field,and the calculated data were qualitatively analyzed and quantitatively studied.Thus summarized,H-type vertical axis wind turbine in the acquisition of aerodynamic performance torque law.By using this rule,it can provide a theoretical basis for the future design and research of the vertical axis wind turbine with higher wind energy utilization rate.According to the latest theoretical research results of vertical axis wind turbine,the flow tube theoretical model is most widely used in the research of vertical axis wind turbine,and it is closer to the experimental data.By continuous improvement and development of the original single-streamtube model theoretical model,the double-disc multi-streamtube theoretical model was finally formed.At present,it has been accepted by many scholars and used as the basis of their own theoretical research.In the research of this dissertation,based on the double-disc multi-streamtube theoretical model,the Matlab program is written to calculate the wind energy utilization rate Cp of the wind turbine and the value of the wind wheel torque M.In this way,the data calculated by Matlab and the data calculated by Fluent software can be comprehensively analyzed,making the conclusion more reliable.Firstly,according to the existing theoretical knowledge of vertical axis wind turbine,the wind wheel,which is the core component of vertical axis wind turbine aerodynamic performance,is designed and its basic parameters are determined.Including the radius of the wind turbine,the number of blades,blade airfoil,blade chord length,height of the wind turbine and other parameters.Then,according to these basic parameters,the two-dimensional and three-dimensional models of the vertical axis wind turbine were established respectively.The grid was divided in the Fluent software,and the inlet boundary conditions were set as speed,outlet boundary conditions as pressure,gas as ideal gas,and incoming flow wind speed as 10m/s.After setting all the boundary conditions,the simulation calculation was carried out.Because the wind wheel moves in a circle when the wind turbine is running,the sliding grid is used to simulate the unsteady flow field of the H-type vertical axis wind turbine.The computing domain is divided into the static domain and the rotating domain,and the two computing domains are connected by Interface.Finally,the velocity and pressure distribution of the fluid around the wind wheel and blade are obtained by simulation.The parameters such as the radius of the wind turbine,the number of blades,blade airfoil and chord length determined in the design of the wind turbine will affect the aerodynamic performance of the vertical axis wind turbine,which is mainly reflected in the influence on the wind energy utilization rate of the wind turbine,the output power and torque of the wind turbine.Therefore,in the fifth chapter of the dissertation,the control variable method is used to study the influence of these parameters on the aerodynamic performance of the wind turbine by changing the value of these parameters in turn.These influence laws provide a theoretical basis for the optimization design of wind turbines.At the end of the dissertation,in order to further the subject further research,my research is put forward,that is before the two vertical axis wind turbines to add a section for streamlined cylinder,the benefits can be achieved in the near wake region of the area,through two wind machine of fluid velocity obviously promoted,so the research has certain research value.