Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 18, 2019 - March 19, 2019
A gravitation vortex type water turbine can generate power with a low head and a small flow rate. However, its flow field is complicated as it has a free surface. So far, we investigated the performance and flow field of this water turbine using a circular tank, and clarified that the runner inlet flow is nonuniform in the circumferential direction. Therefore, we adopted a volute tank whose flow passage cross section gradually narrows from the start of tank winding, and its performance and flow field were investigated by numerical analysis. As a result, the effective head of the volute tank decreased with respect to the circular tank and the turbine output decreased, but the maximum turbine efficiency improved about 18.4%. This improvement in turbine efficiency was revealed that the theoretical effective head decreased but the scale of the vortex generated in the tank decreased and the tank loss was greatly reduced.
