Suppression of Secondary Flows in a Mixed-Flow Pump Impeller by Application of Three-Dimensional Inverse Design Method: Part 1—Design and Numerical Validation

This paper describes the design of the blade geometry of a medium specific speed mixed flow pump impeller by using a three-dimensional inverse design method in which the blade circulation (or rVθ) is specified. The design objective is the reduction of impeller exit flow nonuniformity by reducing the secondary flows on the blade suction surface. The paper describes in detail the aerodynamic criteria used for the suppression of secondary flows with reference to the loading distribution and blade stacking condition used in the design. The flow through the designed impeller is computed by Dawes’ viscous code, which indicates that the secondary flows are well suppressed on the suction surface. Comparison between the predicted exit flow field of the inverse designed impeller and a corresponding conventional impeller indicates that the suppression of secondary flows has resulted in substantial improvement in the exit flow field. Experimental comparison of the flow fields inside and at exit from the conventional and the inverse designed impeller is made in Part 2 of the paper.