Investigation On The Clearance Flow And Dynamic Wear Characteristics Of Pump Casing For Slurry Pump

Slurry pump is widely used in electric power,metallurgy,mining,hydraulic and other industries,mainly used to transport solid-liquid two-phase fluid containing high concentration of solid particles.At present,the design theory of slurry pump is still based on the revision of the design theory of clean water centrifugal pump.Due to the complexity of flow in the pump,there are some prominent problems in the operation of slurry pump,such as low efficiency,easy wear of flow components and short life.Open impeller has good non-blocking performance,and no front cover plate,disc wear is relatively reduced by half,in the slurry pump a large number of use.However,due to the axial clearance,there are complex leakage flows under the action of circumferential and radial pressure differential of blades.The leakage flow and the main flow are coupled to form a complex flow structure.At the same time,due to the presence of solid particles,the clearance flow structure and wear characteristics of the pump body are complex.The boundary of the flow field and change after wear,the wear and the coupling between the flow field,the traditional analysis method is difficult to achieve the actual wear volume and wear life prediction,the slurry pump impeller shaft to the clearance flow and pump body dynamic wear characteristics analysis is of important theoretical and engineering application value,aiming at the shortcomings of the traditional wear prediction method,this study proposes a flow field simulation coupled dynamic abrasion wear prediction and forecasting methods,the main work is as follows:(1)The LCF100/350 chemical slurry pump was selected as the research object and the structured mesh discrete computing domain was adopted.RNG k-? turbulence model and SIMPLE coupling algorithm were used to perform unsteady numerical simulation.Compare the the pressure field,velocity vector and solid particles of the impeller and axial clearance section,we can see that the pressure distribution in impeller are agree with that of the blade axial clearance,and the velocity vector are spiraling.The flow is spiral from the impeller outlet that of the higher pressure areas to the impeller inlet that of the lower pressure areas.Under the action of the pressure difference between the blade pressure surface and the suction surface,the leakage flow is generated.The direction of the leakage flow is opposite to the direction of the mainstream,and the leakage flow is coupled with the mainstream.The leakage vortex is generated behind the suction surface,and the angular vortex is generated near thegap of the blade pressure surface.(2)The dynamic wear model of slurry pump body was established,the dynamic simulation of the wear process of the pump body wall was realized by UDF function,the dynamic update of the clearance mesh movement area was realized by using the dynamic grid technology,and the dynamic wear characteristics of the pump body and the influence of the surface roughness of the pump body on the wear characteristics were analyzed.Pump body wall surface wear numerical simulation results show that the wear and tear strength increases gradually with the increase of the radius,spiraling by the import side extending outward,compare the three kinds of pump under different roughness on the surface of the body wall wear properties,and its maximum wear depth with the surface roughness increases,the maximum wear depth increases with time presents the strong nonlinear,density of the wear rate increased sharply over time.(3)The time coefficient method is introduced to predict the wear amount in the actual time period.With the increase of time,the wear depth increases gradually,and the flow field in the boundary region changes accordingly.The change of the flow field,in turn,affects the change of wear intensity and is coupled with each other,which shows a strong nonlinear relationship of wear depth with the increase of time.According to the actual operation of the model in different time period of wear coefficient of prediction model for nonlinear correction,and the wear depth correction coefficient under different time coefficient of fitting,established the wear prediction model based on time coefficient method,by the example calculation results verify the reliability of the forecasting model,for slurry pump pump body wear life prediction provides a feasible scheme,enrich the theory of slurry pump wear prediction.