Evaluation of through holes blades effect on wells turbine performance for wave energy conversion

Abstract

Abstract The air Wells turbine is one of the most prevalent and promising wave energy harvesting systems. Wells turbine converts the reciprocating energy of the ocean and sea waves into mechanical energy. However, it is characterized by low performance, a narrow operating range, and low efficiency. In this article, the effect of a number of through holes that are distributed along the blade span was evaluated. Typically, the number of holes, diameter, and position from the trailing edge were subjected in this parametric study. The performance parameters of the turbine ( The torque coefficient, turbine efficiency, and stagnation pressure drop coefficient ) were numerically studied at various flow coefficient values to express the Wells turbine performance. The CFD results for a tested turbine model with a blade profile of NACA0015 and solidity of 0.644 were validated against published experimental data. It was found that a turbine blade with seven holes of 2%C in diameter and attached at a distance of 2%C from the trailing edge demonstrated the best performance characteristics. Furthermore, the new through holes blade increased the maximum value of torque coefficient by 1.16 compared to the conventional blade at a flow coefficient of 0.225.