Abrasion Characteristics And Pressure Fluctuations In A Double-Suction Centrifugal Pump In Sandy Flow

Because of some pump stations along the yellow river delivering sandy flow when the centrifugal pump according to the design of transmissing of the water for conveying sand water in the actual work environment, the flow components in the pump is apt to be wear, even perforation, and it affects pressure pulsation in the volute, then aggravates the vibration in the centrifugal pump operating, and noise. In the long term, it is not only can reduce the efficiency of centrifugal pump, but also can shorten the working life of the centrifugal pump, causing great economic losses. So this article on the basis of numerical simulation of the water medium, also made the numerical calculation in the solid-liquid two phase medium, research of impeller blade wear and pressure fluctuation characteristics in volute.This article took a S150-365type single-stage double-suction centrifugal pump as the research object, based on Euler multiphase flow model, used SIMPLE algorithm and standard k-ε turbulence model, carried the pump flowing channel’s out unsteady numerical simulation in water and the solid-liquid two phase medium, researched the degree of wear on blade of the model pump and the pressure fluctuation changes of the monitoring points in volute under different particle concentration and different particle diameter. The research content and achievements were as follows:1、Carried the pump flowing channel’s out the numerical simulation in water, and to validate its performance.2、In the middle of the blade flow set up monitoring points, and collected respectively the relative velocity of sand and particle concentration data of it in different particle concentration and particle diameter, then received the amount of data into the wear calculation formula Wsp=ρCsWms, it can be concluded that blade wear at various points and to know the degree of wear on the pressure surface and suction surface of the blade.3、Each part of the volute set up monitoring points, using CFD technique to curry out unsteady numerical calculation of the model pump flowing channel’s in the water and the solid liquid two phase medium, analysis of the time domain and frequency domain of pressure fluctuation in the volute, compared with the results, can obtain the influence of the pressure fluctuation and changes of pressure fluctuation in different particle concentration and particle diameter. 4、With the particle diameters and solid volume fraction added, the relative velocity and the solid concentration of the blade suction surface is higher than the pressure surface, and it is gradually increased from the front shroud to the back shroud, badly worn parts mainly in the rear of impeller blade suction surface, especially the outlet.5、pressure fluctuation under solid-liquid two-phase flow is greater than the water, and pulse waveform lag of0.002s; With the increased of solid volume fraction, pressure fluctuation is increased gradually, but the amplitude changes is not significant; With the increased of particle diameter, pressure fluctuation is reduced gradually, but the solid phase concentration effect on the pressure fluctuation is huge. From frequency domain, the blade passing frequencies dominate the pressure fluctuation in the volute, and the maximum pressure fluctuation is double of the blade passing frequency.