The effect of turbine geometry on the performance of impulse turbine with self-pitch-controlled guide vanes for wave power conversion

This paper concerns the development of an impulse turbine with self-pitch-controlled guide vanes, which was proposed by the authors to be used as a wave power generator. In order to clarify the effects of rotor blade profile and guide vane pitch/chord ratio on the characteristics of this turbine, experimental investigations were performed using a small-scale turbine. These include three types of turbine blade rotors with different blade inlet angles {gamma} and two types of guide vanes, that is, splitter type and monovane type. The results show that a high efficiency impulse turbine can be achieved for a rotor blade profile with {gamma} = 60{degree}. It is also found that, in this case, the optimum pitch/chord ratio of the guide vane (S{sub g}/l{sub g}) is about 0.8 for the splitter type, and S{sub g}/l{sub g} < 0.65 for the mono-vane type. Furthermore, the effects of the nozzle setting angle and diffuser setting angle on the turbine characteristics have been clarified.