Influence of sand particle size on unsteady characteristics of high specific speed centrifugal pump
In the actual operation environment of centrifugal pump,the sand particles in solid-liquid two-phase flow can directly affect the efficiency and stability of mechanical operation.Therefore taking a centrifugal pump with a specific speed ns=157 as an example,the motion characteristics of different particle sizes of sand in the pump were simulated and analyzed.Firstly,CFturbo and UG software were used for 3D modeling and optimization of the centrifugal pump,and ICEM software was used to divide the model into the whole basin grid to meet the calculation accuracy requirements.Then,ANSYS commercial software was used for pre-calculation processing.Combining with Mixture multiphase flow model and Finnie wear model,five different particle sizes of sand were designed and the full channel simulation was carried out.Finally,according to the simulation results,the motion distribution and wear of different particle sizes of sand in the pump channel and the transient effects onthe pumpwere analyzed.The researchresults showthat inthe range of particle size0.04 mm～0.2 mm,the pump head decreases by about 1.3%and the efficiency decreases by 0.6%～1.5%when the sand particle diameter increases by 0.04 mm.The sand particles mainly gather in the outer trailing edge of the suction surface of the blade,the front cover plate of the pump and the tongue of the volute.The concentration of the sand particles is positively proportional to the particle size.When the sand particle size increases by one gradient,its distribution area on the suction surface can increase by about5%,and the maximum area of the blade can be about35%.Due to structural differences,the low diameter sand particles in the volute flow path are more likely to suspend and accumulate in the flow path,while the large diameter sand particles in the impeller flow path accumulate due to friction.When the particle size is 0.08 mm,the pressure pulsation amplitude and radial force growth rate caused by small diameter sand are smaller than that of large diameter sand.
centrifugal pumpsolid-liquid two-phase flowdistribution of sand movementwear conditionmotion characteristicMixture multiphase flow modelFinnie wear model
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