Experimental investigation of a diffuser-integrated vertical axis wind turbine

Abstract

The increase in energy demand and environmental pollution issues has led to the growth of utilizing renewable energy. Wind energy has become one of the main alternatives for power generation. In order to enhance the performance of the horizontal axis wind turbine (HAWT), the application of a diffuser is one of the innovative methods. At present, research on deploying the diffuser on the vertical axis wind turbine (VAWT) remains scarce. This paper presents the experimental study on the aerodynamic characteristics of a small H-rotor VAWT integrated with a diffuser. The diffuser comprises a pair of flat plates with an inclined angle of 30° at the outlet, with the VAWT is located between the diffuser. A comparison between the turbine performance with and without the diffuser has been conducted. From the experiment, it shows that with the presence of the diffuser, the performance of the VAWT has increased significantly. The power obtained for the bare turbine and with the diffuser is 0.38 W and 0.48 W respectively which is increased by about 26.3% and occurring at 300 rpm. Moreover, with the diffuser, the incoming velocity is also increased. This is due to the presence of the diffuser which enables the flow expansion and creates a low-pressure region at the downwind; inducing a higher incoming wind flow to the VAWT and enhancing its performance. In addition, the rotational speed and a better self-start ability can be achieved with the presence of the diffuser.