Optimization of a turbopump impeller operating at a low specific speed

Abstract

An optimization study on a small-scale turbopump impeller operating at a low specific speed is conducted with the goal of obtaining a high output head at the impeller exit. The outer diameter of the impeller is 56 mm and the impeller operates at 4.0 specific speed (RPM, m3/sec, m) on the design point. For the optimization, the outer diameter of the impeller is maintained constant in order to restrict pump size, and the output head at the impeller exit is chosen to an objective function with eight design variables, which are related with the design of the impeller shape. The response surface method is used for the optimization scheme, and three-dimensional incompressible turbulent flow within the impeller is computed for a numerical analysis. The output head of the objective function obtained with an optimized impeller is increased by 9.7% compared with that obtained with an impeller designed with typically recommended values for design parameters. This increment is caused by reducing the recirculation flow region within the impeller passage. ? 2007 Pushpa Publishing House.