Pressure and momentum field investigation of a centrifugal pump through dynamic loading of a semi-open impeller

Abstract

A study was performed to investigate the variation in the forces and moments acting on the front and back sides of a semi-open impeller. Three rotational speeds and five volumetric flow rates for each speed were identified as the operating conditions for the pump after generating performance curves. The pressure distribution inside the pump housing was measured through pressure taps drilled in the front and back housing. These pressure measurements were obtained for distinct geometric configurations comprising of varying positions of the impeller and the front housing. Pressure contour plots were generated for all the operating conditions and an asymmetric pressure distribution was observed in the pump housing. Higher pressures were witnessed near the volute tongue. Forces acting on the impeller were calculated by integrating the pressures acting on it as measured by the pressure taps. A net axial thrust on the impeller, trying to push it towards the suction side, was observed, which decreased in magnitude with increasing back clearance for a certain fixed value of the front clearance. Moments acting on the front and back sides of the impeller were noticed to approach smaller magnitudes for higher volumetric flow rates. A geometric configuration was identified for better overall performance of the pump.