Abstract
Vertical axis wind turbine (VAWT) is a competitive power generation device due to structural simplicity, wind direction independence, no yaw mechanism required, easier maintenance, and lower noise emission. However, blade tip vortex will be generated at both ends of the blade during the rotation, resulting in torque loss and efficiency reduction. In this paper, computational fluid dynamics is used to study blade tip vortex and its reduction technique of a single-blade VAWT rotor in real scale. By monitoring the force and flow field at different heights of the blade, the influence ranges of tip vortex are obtained. The reduction effect of the bulkhead obtained from the blade profile curve is studied, and the size of the bulkhead is optimized. On the basis of adding the optimal bulkhead, the influence of the supporting strut is also explored. The joint action is obtained by changing the location of the supporting strut. The results show that the top supporting strut-bulkhead structure is the optimal position. The power-extraction efficiency of the rotor with this integrated structure is significantly improved at optimal tip speed ratios (TSRs) and higher TSRs.
Highlights
Wind power is one of the solutions to energy problem as a clean energy source with large reserves in nature
Hamada et al [8], Howell et al [9], and Lam and Peng [10] compared the torque generated by blade between 2D and 3D computational fluid dynamics(CFD) models, and obtained the conclusion that the 3D effects significantly reduced the extraction rate of wind power
Yanzhao Y et al [11] studied the effects of tip vortex on the wake of a two-blade vertical axis wind turbine (VAWT) with different tip speed ratios (TSRs) by CFD simulations
Summary
Wind power is one of the solutions to energy problem as a clean energy source with large reserves in nature. Tip vortex is part of the three-dimensional unsteady flow, which constantly sheds in each blade revolution, decreasing the torque and causing structural vibrations. Hamada et al [8], Howell et al [9], and Lam and Peng [10] compared the torque generated by blade between 2D and 3D computational fluid dynamics(CFD) models, and obtained the conclusion that the 3D effects significantly reduced the extraction rate of wind power. Yanzhao Y et al [11] studied the effects of tip vortex on the wake of a two-blade VAWT with different tip speed ratios (TSRs) by CFD simulations. Considering the 3D effect caused by supporting strut, some research was undertaken in terms of the cross section and location of the strut [8,16,20,21,22]. The results show that the more streamlined hydrodynamic strut section provides lower strut drag
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