渦巻タンクを有する重力渦式水車の性能と流れ場に及ぼす羽根枚数の影響

抄録

A gravitation vortex type water turbine is a water turbine that guides water into a tank and generates power by the gravitational vortex generated in the tank. Although this water turbine can be generated by a low head and a smallness flow, the flow field is a complicated thing which has a free surface. We researched Influence of number of blades on performance and flow field of this water turbine a circular tank. However, influence of number of blades on this water turbine with a volute tank with improved performance has not been elucidated. In this study, we performed the free surface flow analysis of this water turbine with a volute tank and investigated performance and flow field with each number of blades. As a result, the turbine efficiency of this turbine was highest when the number of blades was 20, and showed a tendency different from that of the circular tank. In addition, as the number of blades increased, the loss inside the impeller increased sharply, but the loss at the outlet of the tank decreased significantly. Therefore, when the number of blades was 20, the total hydraulic loss was the smallest, and the hydraulic efficiency and the turbine efficiency were the highest.