Wells turbine for wave energy conversion - improvement of stall characteristics by the use of 3-dimensional blades

The effect of 3-dimensional blade on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions and simulated numerically by quasi-steady analysis under sinusoidal flow conditions, in order to improve the stall characteristics of Wells turbine for wave energy conversion in the study. Aim of the use of 3-dimentional blade for Wells turbine is to prevent flow separation on the suction surface near tip. 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 2-dimensional blades. As a result, it has been concluded that both the efficiency and stall characteristics of Wells turbine can be improved by the use of 3-dimensional blade.