Design and Analysis of 3D Blades for Wells Turbine

Wells turbine is a self-rectifying air turbine which is widely used in oscillating water column energy converter. The Wells turbine will always rotate in the same direction irrespective of the direction of the oscillating airflow. Furthermore the Wells turbine has a simple configuration and structure. This is why the Wells turbine is very commonly used for conversion of wave energy. At present 2-dimensional blades are being used for the conversion of wave energy. We are proposing 3-dimensional blades that can improve the steady characteristics of the current wells turbine. The effect of 3-dimensional blade on the turbine characteristics has been analyzed based on different inlet velocities and steady characteristics were found out. Further, the aim of the use of 3-dimentional blade for Wells turbine is to prevent flow separation on the suction surface near tip, which is a major drawback in the case of existing one. The chord length is constant with radius and the blade thickness increases gradually from hub to tip. The blade profiles are NACA0015 at hub, NACA0020 at mean radius and NACA0025 at tip. The performance of wells turbine with 3-dimensional blades has been compared with those of original Wells turbine, i.e., the turbine with 2dimensional blades. As a result, it has been concluded that both the efficiency and turbine characteristics can be improved by the use of 3-dimensional blade.