Effect of impeller front shroud perforation on gas-liquid two phase flow performance of the multistage side channel pump

Abstract

To enhance the gas-liquid mixed transport performance of the first-stage centrifugal impeller of the multistage side-channel pump, a diagonal perforation oriented towards the exit is fabricated in the front shroud of the impeller. Based on the Euler-Euler non-homogeneous model and the SST k -ω turbulence model, the gas-liquid two-phase unsteady numerical simulation of the internal flow under various inlet gas volume fraction (IGVF) is conducted, the reliability of the simulation is verified through comparison with experiments. The results indicate that under the circumstances of high flowrate and high IGVF, the perforation design of the front shroud can increase the head of the centrifugal impeller by 4%–7% while the efficiency is slightly decreased under gas-liquid two phase flow. According to the internal flow analysis and Liutex vortex identification, the high-pressure and high-speed fluid in the front pump chamber is introduced into the impeller through the front shroud perforation, smashing and dispersing the originally aggregated bubble groups in the flow channel, causing the average pressure in the impeller to rise after the perforation, increasing the number and intensity of vortexes, significantly reducing the number and the accumulation area of bubbles, greatly reducing the air volume fraction of the impeller. The bubble blockage phenomenon in the flow channel is observably improved, and the gas-liquid mixed transport capacity of the centrifugal impeller is significantly enhanced, providing a theoretical basis for the optimization design of the gas-liquid two-phase flow of vane pumps.