Optimization Design Of New Type Of Combination Vertical Axis Wind Turbine

wind energy is the most grown technique among renewable energy. As the main direction of the new energy source,wind energy has agreat application foreground.Wind turbine is the main form of use of wind energy. horizontal axis wind turbine (HAWT) and vertical axis wind turbine (VAWT) are the basic forms of the wind turbine. At present, horizontal-axis wind turbine is widely used, But researchers pay more and more attention to the vertical-axis wind turbine for its excellence performance.Vertical axis wind turbine (VAWT) divided into the resistance-type vertical axis wind turbine and lift-type vertical axis wind turbine. Lift-type vertical axis wind turbine is high efficiency,but it start difficultly in low speed of wind. resistance-type vertical axis wind turbine start easily in low speed of wind,but its efficiency is low. In view of the advantages and disadvantages of the two types of vertical axis wind turbine,this paper designs a new type of combination vertical axis wind turbine,its contains a Darrieus wind turbine and a Savonius wind turbine,then the numerical simulation and blowing experiment are applied. The main work and results are as follows:1. The optimization design of Darrieus wind turbine and Savonius wind turbine have been made, and determined the parameters of the structure. Established the model of the wind turbine according to the calculation of the geometry parameters of the structure,select overrunning clutch as the connection unit.2. The NACA0015airfoil were selected as the research objects in Darrieus wind turbine in this paper. and the steady flows around the airfoil were two-dimensional simulated, and the turbulence was treated separately by using Spalart-Allmaras model, and analyzes the aerodynamic characteristics of the airfoil, compared with the reference experimental data.The results showed that the result is accurate.3. The two-dimensional and three-dimensional numerical simulation on unsteady rotated flow of the vertical axis wind turbine with or wituout Savonius wind turbine were done base on sliding meshes by means of the software Fluent, and the turbulence was treated separately by using k-epsilon model.The simulation results show that the flow distribution is very unsteady,due to the factors,such as tip loss,the three-dimensional numerical simulation of the wind power coefficients is lower than the results of the two-dimensional numerical simulation.After installing the Savonius wind turbine, the wind power coefficients and the rated power are decrease,but the torque is increase.4. To study the actual performance of the combination vertical axis wind turbine,the experiment made for the wind turbine with or wituout Savonius wind turbine respectively,shows that install the Savonius wind turbine,although the wind power coefficients and the rated power are decrease,but the combination vertical axis wind turbine’s torque increase,and the combination vertical axis wind turbine start easily in low speed of wind. the experimental results and the simulation results are close.