Effect of Volute Geometry on Radial Force Characteristics of Centrifugal Pump during Startup

Abstract

To research the effect of the volute geometry on the radial force characteristics of the centrifugal pump during the starting process, choosing a centrifugal pump with a head of 87m as the research object. The pumpingchamber is redesigned into a single-volute and a double-volute with similar external characteristics, and acirculation pipeline system is established. RNG k-ε turbulence model is employed to calculate the unsteadystarting process of two kinds of centrifugal pumps. The variation trends of radial force received by the impellerand volute during the start-up process are obtained. The radial force characteristics and internal flow fieldevolution of two centrifugal pumps are compared and analyzed. The results show that the radial force vectordistribution of the impeller changes in spiral periodicity during the startup process, and the spiral geometry isinfluenced by the number of impeller blades. The direction of the spiral is opposite to the rotational speed. Thedouble-volute geometry can effectively reduce the radial force and pulsation amplitude of the impeller duringthe start-up process of the centrifugal pump, reducing the radial force by about 80% at rated speed. But theradial force vector distribution of the double-volute is more complicated and disordered than the single-volute