Inverse Design of Impeller Blade of Centrifugal Pump with a Singularity Method

The singularity method has been extensively applied into an analysis of the potential flow through centrifugal pump impellers, i.e. direct problem, but it was little utilized in inverse design of such impeller blades, i.e. inverse problem. In this paper, a singularity method was applied for inversely designing impeller blades. A cubic Bezier curve was established to express mathematically density function of bound vortex intensity along the blade camber line so as to get a smooth and loading carefully controlled blade. The angle of attack and blade loading coefficient were taken into account in the given density function of bound vortex intensity. The direct and inverse problems have been validated with a typical experimental centrifugal pump impeller. Furthermore, the impeller blades were redesigned by using the method, and the three-dimensional turbulent viscous flows inside the original and redesigned impellers were calculated numerically by means of a CFD code Fluent. It was shown that the blade shape and flow pattern on the blade can be controlled easily by altering the density function of bound vortex intensity. The CFD outcomes confirmed that the original impeller hydraulic efficiency was improved by 5% at the design duty, but 9% at off-design condition