Performance enhancement of an H‐Darrieus vertical axis wind turbine via moving surface boundary‐layer control

Abstract

The moving surface boundary-layer control method (MSBC) is a kind of active flow control methods that overcomes the adverse pressure gradient and suppresses the flow separation by directly energizing the boundary layer near the moving surface. In this study, computational fluid dynamics simulations were performed to investigate the feasibility of using MSBC to improve the aerodynamic performance of a straight-bladed H-Darrieus vertical axis wind turbine (VAWT). In doing so, a segment of the original surface of the VAWT blade was then replaced with a moving surface. Influences of different geometric and motion parameters of moving surface, including location, length, velocity ratio, and groove depth on the net power coefficient of VAWT, were systematically studied. Moreover, the sensitivity of different parameters to the net power coefficient of VAWT at the optimal tip speed ratio was analyzed via the orthogonal design method. As a result, the optimal combination of moving surface parameters was able to be determined. The present results show that the maximum net power coefficient of VAWT having blades with partially moving surface can be increased by 22.8% compared with that of the baseline VAWT. In addition, the effectiveness of two active flow control methods, co-flow jet and moving surface, in improving aerodynamic performance of a VAWT was also compared. It is found that MSBC method has the potential to achieve superior control performance and promote the energy utilization coefficient of the VAWT more effectively by using comparatively less external energy input.