The Design and Analysis of the Wells Turbine in an Oscillating Water Column Wave Power System

The Design and Analysis of the Wells Turbine in an Oscillating Water Column Wave Power System

Wave energy is a type of marine renewable energy, and an Oscillating Water Column wave power system (OWC) is a converter with higher efficiency. The turbine in the system determines the efficiency of energy conversion and directly affects the performance of wave power generation. This paper presents the study conducted on the widely-used Wells turbine in an oscillating water column wave power system and the blade design method with evaluations and performance comparison of designs. In this paper, different designs were carried out by both potential flow and viscous flow methods, and the performance of each was confirmed and compared. It has been found that the design with a camber distribution is better than the reference geometry without a camber distribution. The average torque and efficiency are close to the reference geometry, but the stall is delayed. Next, the blades designed with an optimized skew distribution have achieved better performance than zero-skew distribution. The mean torque coefficient is increased from 0.057 to 0.125, and the mean efficiency coefficient is increased from 0.452 to 0.483 with the designed skew distribution. Finally, a comparison between single-stage and contra-rotating turbines has been conducted, and although contra-rotating turbines generate greater torque, they have lower efficiency.