Optimum values of design variables versus specific speed for centrifugal pumps

Abstract

An optimal design code for centrifugal pumps has been developed to determine the geometric and fluid dynamic variables under appropriate design constraints. The optimization problem has been formulated with a non-linear objective function to minimize one, two or all of the fluid dynamic losses, the net positive suction head required and the product price of a pump stage depending on the weighting factors selected as the design compromise. The optimal solution is obtained by means of the Hooke-Jeeves direct search method. The performance analysis is based on the mean streamline analysis using the present state-of-the-art loss correlations. The optimized efficiency and design variables of centrifugal pumps are presented in this paper as a function of non-dimensional specific speed in the range, 0.5 less than or equal to N-s less than or equal to 1.3. The diagrams presented herein can be used efficiently in the preliminary design phase of centrifugal pumps.