Influence of Impeller Wear Ring Clearance on Axial Force in Low Specific Speed Centrifugal Pump

摘要

Axial force of centrifugal pump affects significantly performance and reliability of the pump.Excessive axial force causes the axial moving, which makes impeller strike on the surrounding shell.Wear ring is amounted between the impeller and pump body.The fluid leaking from the clearance of wear ring will flow into the impeller inlet directly and impact the mainstream at inlet.In this paper, the method of numerical simulation is adopted to find the influence of wear ring clearance on axial force in low specific speed centrifugal pumps.Based on RANS and the RNG k-ε turbulence model as well as the SIMPLE algorithm, the fluid flow in model prmp is numerically simulated, and the characteristics of axial force are analyzed.The results show that the main component of the total axial force is due to asymmetric pressure distribution on outer surface of impeller.The performance of centrifugal pump will decline with the increasing of wear ring clearance.Axial force is the minimum when the clearance is maximum, but leakage increases with the increasing of clearance.Furthermore, it will lead to obvious backflow at inlet and pressure decreasing on outer surface of impeller.The study provides technical support and theoretical basis for wear ring's structure and axial force equilibrium structure's optimization and design.