Numerical Simulation And Analysis Of Solid-liquid Two-phase Unsteady Flow In Screw Centrifugal Pump

Screw-type centrifugal pump is a new kind of slurry pump with such excellentcharacters as non-clog, no winding and injury. It has been widely used in sewagedischarge and food, paper and other industrial department. The major differencebetween screw centrifugal pump and ordinary centrifugal pump lies in the screwcentrifugal impeller which has the double virtues of screw pump and centrifugal withits unique structure.At present, the numerical simulation of solid-liquid two-phase flow in the screwcentrifugal pump mainly focus on steady flow in the domestic, although thecharacteristics of the internal flow field can be reflected to a certain extent, but itdoesn’t entirely true reaction to screw centrifugal pump for complex internalflows,this caused a lack of precision to analysis internal characteristic, thus onimproving the external characteristics of the screw centrifugal pump had a negativeimpact. This subject intends to numerical calculation in the screw centrifugal pump ofthe solid-liquid two-phase unsteady flow, to get more reflect the true significance ofthe physical solid-liquid two-phase flow characteristics of the flow field inside thescrew centrifugal pump, In order to improve its performance to provide a theoreticalbasis and reference.The main contents of this subject as follows:1、According to the structural characteristics of screw centrifugal pump and theinternal flow field characteristics, ignore the gap flow between the wheel hub and thelatter wheel guard, Internal flow of the screw centrifugal pump has been simplified,and divides it into the import area, the impeller area, the volute area three regions.2、150×100LN-32Screw centrifugal pump is modeled three-dimensionally byPRO/E and ICEM is be used to division of the three flow regions, respectively,thenmergered in FLUENT.3、The solid-liquid two-phase unsteady flow in a screw centrifugal pump wassimulated and obtained external characteristics and internal flow field of screwcentrifugal with the rotation of the impeller at different times.4、Analysis of internal multiphase flow field in the screw centrifugal pump with5kinds of different flow and5kinds of different solid volume concentration, Toobtain influence on its external characteristic and the internal flow field with differentflow and different concentration of the solid volume. The innovations of this project are as follows:1、Conducted in deep study of multiphase flow with150×100LN-32screwcentrifugal pump，proposed using mixture model, standard k εmodel, unsteadyReynolds averaged Navier-Stokes equations and sliding mesh technology to numericalsimulate.2、Obtain the pressure pulsation、axial force、radial force and other inductionforce characteristics of screw centrifugal pump by setting the monitoring points.The conclusions of this project are as follows:1、Unsteady numerical calculated of a water medium in the rated conditions ofone cycle obtained the fluctuations of head、efficiency、axial force and radial forcewith the phase of impeller; the variation of the pressure on the middle section ofvolute and flow channel cross-section flow line with of the rotation of the impeller atdifferent times.2、 Unsteady numerical calculated of solid-liquid two-phase medium underdifferent flow obtained the variation of pressure on volute outlet、axial force、 radialforce and torque with the flow change in one cycle. Analysis of the variation of thepressure on the blade faces, back, volute section and the solid volume concentration indifferent times under different flow.3、 Unsteady numerical calculated of solid-liquid two-phase medium underdifferent solid volume concentration obtained the variation of pressure on voluteoutlet、axial force、radial force and torque with the solid volume concentration changein one cycle. Analysis of the variation of the pressure on the blade faces, back, volutesection and flow channel cross-section flow line in different times under differentsolid volume concentration.