Flow and performance characteristics of a direct drive turbine for wave power generation

A cross-flow turbine, also known as Banki turbine, is a hydraulic turbine that may be classified as an impulse turbine. It has gained interest in small and low head establishments because of its simple structure, cost effectiveness and low maintenance. The present work expands on this idea and aims to implement a cross-flow turbine as Direct Drive Turbine (DDT) for wave power generation. Waves have enormous amount of energy which is environment-friendly, renewable and can be exploited to satisfy the energy needs. A Numerical Wave-tank (NWT) was used to simulate the waves using the commercial CFD code ANSYS-CFX. The base model was firstly studied at five different wave periods without the turbine. The highest water power (PWP) of 32.01 W was recorded at T=3 s. A cross-flow turbine was then incorporated and the simulation was validated at T=2 s. In addition to this, the performance of the turbine at T=2.5 s and T=3 s at different turbine speeds was also studied. The highest turbine output power of 14 W was recorded at a turbine speed of 30 rpm at the wave period of 3 s, giving a turbine efficiency of 55%.