Flows of air bubbles and solid particles entrained in a mixed-flow pump.

Abstract

If air bubbles or solid particles are entrained in a pump, they will cause degradation of the pump performance as well as erosion damage to its materials. This paper concerns the theoretical estimation of the three-dimensional movements of the particles entrained in a mixed-flow pump. The particle motions were numerically decided by a finite element method for water flow under the assumption of potential flow, and then by integration for equations of particle motion. The trajectories of air bubbles generally coincide with the streamlines of water ; however, they deviate considerably from the shround to the hub at the pressure side of the impeller blade. The solid particles move straight forward irrespective of the curvature of the water streamline, and collide with the hub surface.