Abstract
In order to improve the water quality environment of the stagnation waters such as reservoirs and dams, the floating vertical pump was developed. In this study, first of all, the influence of the setting angle of the impeller on the fluid dynamic characteristics of this pump is clarified. Moreover, the characteristics of the pump were applied as the boundary conditions to the numerical simulation on the circulating flow in a water tank. The static pressure and the flow rate of the pump are raised up to approximately 40° according to the setting angle. The static pressure on the pressure surface side of the blade also rises at the blade tip side until 40°; on the other hand, the pressure on the pressure surface side does not rise when the setting angle becomes more than 40°. When the angle becomes more than 40°, the domain of the low pressure of the suction pressure side has been expanded by the vortex formed to the blade tip side. It is considered that the static pressure of the pump receives the influence of the increase of the slipping velocity according to the expansion of the vortex on the blade tip side. It clarified that the strong circulation can be formed with the suitable setting angle of the blade in the range of flow rate that the flow around the impeller does not separate.
