Effect of wave conditions on the performance and internal flow of a direct drive turbine

The purpose of the present study is to investigate the effect of wave conditions on the performance and internal flow of a newly developed direct drive turbine (DDT) model for wave energy conversion experimentally. All the experiments using the test turbine models are conducted in a 2-D wave channel. Monochromatic waves of various conditions of wave height and wave period are applied to the turbine performance test. The influences of turbine configuration on turbine performance are also investigated. Test results show that rotational speed, differential pressure, incident flow rate, maximum output power, and best efficiency of the turbine model vary considerably depending on the wave conditions. Installation of a front guide nozzle and a rear water reservoir to the test turbine improves the turbine performance. Large passage vortex occurs both at the front and rear turbine nozzles in turn through a reciprocating flow in the turbine passage.