Effect of blade installation angle on power efficiency of resistance type VAWT by CFD study

International Journal of Energy and Environmental Engineering, Oct 2014

Renewable energy is an inevitable choice to meet the demands of energy resource. In the 21st century, one of the serious problems facings us is the energy resources that restrict the social progress and sustainable development. Environmental pollution and fossil energy resources shortage force people to explore and use new energy resources. The aim of this paper is to study the effect of blade installation angle on power coefficient of a five-blade resistance type vertical axis wind turbine using CFD simulations. The computation is conducted for the turbine with the blade diameter of 0.76–0.86 m and the turbine radius R = 2 m. The results show that the maximum value of power efficiency of 28.48 % can be obtained when the installation angle is 19° for the five-blade resistance type vertical axis wind turbine with the blade diameter of 0.78 m and the turbine radius R = 2 m.

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Effect of blade installation angle on power efficiency of resistance type VAWT by CFD study

Int J Energy Environ Eng Effect of blade installation angle on power efficiency of resistance type VAWT by CFD study Maosheng Zheng 0 1 Yusheng Li 0 1 Yangyang Tian 0 1 Jun Hu 0 1 Yuan Zhao 0 1 Lijun Yu 0 1 0 M. Zheng Y. Zhao Institute of Shaanxi Energy Resource and Chemical Engineering , Xi'an 710069 , China 1 M. Zheng (&) Y. Li Y. Tian J. Hu Y. Zhao L. Yu Institute for Energy Transmission Technology and Application, School of Chemical Engineering, Northwest University , Xi'an 710069 , China Renewable energy is an inevitable choice to meet the demands of energy resource. In the 21st century, one of the serious problems facings us is the energy resources that restrict the social progress and sustainable development. Environmental pollution and fossil energy resources shortage force people to explore and use new energy resources. The aim of this paper is to study the effect of blade installation angle on power coefficient of a five-blade resistance type vertical axis wind turbine using CFD simulations. The computation is conducted for the turbine with the blade diameter of 0.76-0.86 m and the turbine radius R = 2 m. The results show that the maximum value of power efficiency of 28.48 % can be obtained when the installation angle is 19 for the five-blade resistance type vertical axis wind turbine with the blade diameter of 0.78 m and the turbine radius R = 2 m. CFD; VAWT angle; Power coefficient; Resistance type; Installation List of symbols R Wind turbine maximum radius (m) r Radius of the blade (m) d Diameter of blade (m) L The length of the computation region (m) H The width of the computation region (m) Constant equal to 0.6125 Power coefficient Power produced by the turbine (w) Torque coefficient Inlet wind speed (m/s) Rotor rotational rate of turbine (rpm) Rotor swept area (m2) Air density (kg/m3) Installation angle of the blade ( ) Introduction In the 21st century, one of the serious problems facing us is the energy resources that restrict the social progress and sustainable development. Environmental pollution and fossil energy resources shortage force people to explore and use new energy resource. Renewable energy and sustainable development is a common concerned subject of the whole world. Wind energy is one of the most promising resources of renewable energy, many countries have grant plan to explore and use it due to its great advantage of pollution free, abundant availability and conversion locally, etc. It can thus help us to reduce environmental pollution and the dependency on fossil fuels [ 1 ]. The most application of wind energy is to generate electrical power through various types of wind turbines. Wind turbines can be classified into two families generally, i.e., the horizontal axial wind turbine (HAWT) and the vertical axial wind turbine (VAWT) [ 2 ]. A lot of study has been focused on HAWT till now, while the study of VAWT is relatively rare. However, VAWT has its greatest advantage of ‘‘omnidirection’’. Although the propeller-type windmill could provide a larger power output, it needs greater wind velocity that is almost impossible in city. Besides, HAWT induces low frequency noise that is harmful to animals. It also has a weak response to temporal changes of wind velocity and direction. However, VAWT escapes these environmental problems, resulting in their use in urban environments. Savonius type is one of the oldest types of the VAWT. It has been studied since the pioneer work of Savonius. Although the Darrieus type Vertical Axis Wind Turbine is more efficient than the Savonius type, the several advantages of Savonius type are still attractive, such as good starting torque, simple mechanism, lower rotation speed, and omnidirectional characteristics [ 3 ]. Unlike the Darrieus type of wind turbines, the Savonius type wind turbine is commonly considered as a drag-driven type of wind turbine. The general theory of the Savonius turbine is simple. The wind exerts a force on a surface and this surface is then moved around an axis. Mahmoud et al. [ 4 ] studied the Savonius rotor performance experimentally, it was found that, the two-blade rotor is more efficient than three and four ones. The rotor with end plates gives higher efficiency than those of without end plates. Double stage rotors have higher performance compared to single stage rotors. The rotors without overlap ratio are better in operation than those with overlap. Zhao et al. [ 5 ] also studied the influence of blade number on power efficiency of Savonius turbine numerically, it was found that, the two-blade rotor is more efficient than three ones as well, and they clarified that the actual reason for the blade number influence is induced by the ‘‘shading effect’’. From flowing field analysis, it is found that the effective concave winding area of the blade decreases due to the shading of the nearby blade for the three-blade Savonius turbine, while the effective convex winding area of the blade increases du (...truncated)


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Maosheng Zheng, Yusheng Li, Yangyang Tian, Jun Hu, Yuan Zhao, Lijun Yu. Effect of blade installation angle on power efficiency of resistance type VAWT by CFD study, International Journal of Energy and Environmental Engineering, 2015, pp. 1-7, Volume 6, Issue 1, DOI: 10.1007/s40095-014-0142-0