Effect of blade shape on hydraulic performance and vortex structure of vortex pumps

The vortex pump has increasingly become an important alternative or supplement to the centrifugal pump, the positive displacement pump and the diffusion pump due to its capacity of developing a high head at a small flow rate within a single stage. However, the vortex pumps with various blade shapes such as the twisted blades or the 3-D blades are not well studied. In this paper, some new concepts of the 2-D and 3-D corner blades are introduced for the design of the vortex pumps. The mechanism behind the effect of the corner blade shapes on the pump hydraulic performance is numerically investigated and elucidated in terms of the internal vortex structures. The results show that both 2-D and 3-D forward corner blades can induce stronger well-organized longitudinal vortices as well as smaller axial and radial vortices within the impeller blade passage, which benefit a higher pump head and a higher efficiency in comparison with the traditional radial straight blade. This study provides useful guidelines for the design of advanced vortex pumps.