Study On Wear Of Hydraulic Components Of A Slurry Pump Under Off-design Operating Conditions

The slurry pump is responsible for transporting high-concentration slurry for the ore grinding and recycling system in the beneficiation process of copper,iron,and coal mines.The most representative slurry pump is the overflow pump of the ball mill.This type of pumps is at the forefront of the mineral processing process.The slurry it transports contains large ore particles with high hardness and has high solid phase concentration.The hydraulic components are often found to be severely worn,especially when the pump operates under off-design conditions.The service life of the hydraulic components is short,which poses a great threat to normal operation of the whole system.Therefore,the research on the mechanism of the solid-liquid two-phase flow and wear characteristics of the slurry pump operating under off-design conditions is not only of theoretical significance,but also of engineering importance.In the presented thesis,the ESH650 centrifugal mill overflow pump,which conveys the slurry of the mill to the cyclone,is selected as the research object.The Eulerian-Eulerian Particle multiphase flow model is employed,and the computational fluid dynamics(CFD)software ANSYS CFX is used to study the solid-liquid two-phase flow in the pump under off-design operating conditions.The CEL(CFX Expression Language)function of ANSYS CFX is used to introduce the empirical wear formula into the post-processing module.Based on the numerical results,wear of each hydraulic component of the pump is quantified.Furthermore,the mechanism underlying the wear is explained.Firstly,a three-dimensional geometric model is established to describe the flow domain of the pump.Meshes are deployed in the flow domain.At certain solid-phase concentration and particle size,numerical simulations are performed separately under the design,low flow rates,and large flow rate conditions.Wear patterns are numerically obtained.In combination with practical experience of the pump application,the reasons of intensified wear of the hydraulic components under off-design conditions are explained.Secondly,hydraulic optimization schemes of the pump under low flow rate and large flow rate conditions are proposed,respectively.At certain solid phase concentration and particle size,wear of the pump associated with the optimized schemes is calculated.Based on a comparative analysis,the wear intensity is decreased as the original schemes are replaced with optimized ones.An empirical formula is proposed in the thesis to calculate wear of hydraulic components per unit operation time.The data obtained is validated through the experimental results.The results obtained provide a sound support for deepening the understanding of hydraulic components of the slurry pump,and serve as a reference for the optimization design aiming to improve the anti-wear performance of the pump.