Design And Performance Research On A Vertical Axis Wind Turbine With Wind Collection Pattern

As a clean and renewable energy, wind energy has a broad application prospect. At present, the wind power is the most mature way of using wind energy. Currently, the mainstream model of wind power generation is the horizontal axis wind turbine (HAWT). With the characteristics of high start-up wind speed and running noise, the HAWT can not effectively use the wind energy resource in low-speed wind areas, living areas and the cities. Traditional resistance-type vertical axis wind turbine (VAWT) has the advantages of simple structure, the starting wind speed and running noise which are lower than the horizontal axis wind turbine, it is suitable for using in low wind speed areas, living areas and the cities. However, the disadvantages of low coefficient of wind power (Cr) limits its development. In order to improve Cp of the traditional resistance-type VAWT, this thesis designs a VAWT with wind collection pattern by improving its structure. The VAWT with wind collection pattern contains a wind collection device and a wind wheel.Firstly, this paper describes how to use numerical simulation technology to analysis the performances of VAWT. Meanwhile, we also discuss the feasibility of the design of the wind turbine which have the same cross-section in axial direction by using the two-dimensional numerical simulation in place of the three-dimensional numerical simulation.Secondly, the structure and working characteristics of the VAWT with wind collection pattern are analyzed in this thesis. With the help of FLUENT software and the orthogonal experimental design, the VAWT with wind collection pattern is optimized design. Optimization is divided into two steps:the one of them, the wind wheel is optimized design based on CAD spline curve modeling technology; the other step, designing the wind collection device for optimal wind wheel. The two forms of the wind collection device are introduced, and their design parameters are optimized separately. The best form of the wind collection device and its design parameters are obtained by optional design for the wind collection device. In addition, the relatively optimal VAWT with wind collection pattern is provided. The results show that the output power of the VAWT with wind collection pattern is157%as large as the traditional resistance-type VAWT under the same conditions.In the end, the performances of VAWT with wind collection pattern are considered in this thesis. Firstly, the reasons for the improvement of the Cp of the VAWT with wind collection pattern are analyzed from the point view of the flow field. Then, the startup characteristics of the VAWT with wind collection pattern are studied and the results show that the startup characteristics of VAWT with wind collection pattern have been improved, and its starting wind speed is lower than the traditional resistance-type VAWT. The Cp of some vertical axis wind turbines with wind collection pattern which have different ratios of height and diameter are calculated and the best ratios of height and diameter is obtained in this paper. Moreover, in order to provide the selection of appropriate generator and guidance for the wind turbine operation control strategy, the performance of VAWT with wind collection pattern working under different conditions are studied. Finally, in order to expand the range of working wind speed of the VAWT with wind collection pattern and improve its generating capacity, the idea which the guide vanes may be designed as rotatable is proposed. In particular, its feasibility is also analyzed in this thesis.