Improvement of compact Darrieus-type hydraulic turbine for extra low head by changing inlet shape

Abstract

Hydraulic power generation has a potential as an environmental friendly energy, which is not discharging a carbon dioxide gas during operation. Currently, high and middle water head turbine has been fully developed in practical use. However, extra low head hydraulic turbine has not been developed yet as a commercial utilization. Compact Darrieus-type hydraulic turbine has been focused on for small waterway. The purpose of this study is to improve the performance of the compact Darrieus-type hydraulic turbine, by changing inlet shape. In our previous study, the blade shape, the number of blades, the water wheel diameter ratio of chord length and pitch circle radius are optimized. The purpose of the present study is to further improve the performance of the compact Darrieus-type water turbine based on former results. In this study, the inlet shapes were changed to increase inflow velocity and to contribute improvement of efficiency. As a result, the efficiency of the turbine with using only half side counterpart nozzle was increased compared to the other settings.