Numerical Simulation Of Solid-liquid Two-phase Flow With Transporting Large Particles In A Centrifugal Pump

Due to the solid particles are existed in the medium of solid-liquid two-phase flow centrifugal pump in the practical application,the efficiency of the pump is low. The wear problem of particles will lead to poor reliability when the pump is in operating. Though a lot of scholars about solidliquid two-phase flow pump is developed,but the two-phase turbulent flow characteristic and flow channel of the centrifugal pump are the complicated and the parameters of solid phased is different. The motion of solid phased particles and the abrasion mechanism of centrifugal pump are still not be revealed well. Therefore it is very necessary to research the internal flow of the solid-liquid two-phase flow pump in depth and provide the theoretical reference of designing a reliable pump with good erosion property.In this dissertation, a M196-100 solid-liquid two-phase flow centrifugal pump was regarded as the research object. The main force of the particles in the process of transporting in the flow field were analyzed. According to the volume force which needed to be considered in the calculation, the particle motion equation was determined. The discrete phase model(DPM) and RNG k- epsilon turbulence model were applied in the numerical calculation of solid-liquid twophase flow. The internal flow characteristics of centrifugal pump and the erosion property of flow components were analyzed, the main research contents and results were as followings:1. The flow channel of centrifugal pump was modeled with Pro/E software, then flow model with was meshed Gambit software. Finally the numerical calculation was computed under the medium of single phase condition in centrifugal pump by using Fluent(CFD software). Compared the numerical results of hydraulic head and efficiency with the experimental results to verify the reliability of the calculation model in numerical simulation.2. In order to research the influence of added mass force on the movement of particle and the internal two-phase flow of centrifugal pump while the particle volume effect was enhanced with the particles diameter increasing, the unsteady numerical calculation in a solid-liquid two-phase flow pump was conducted with two kinds of schemes under different particle diameter. The two kinds of schemes were introducing the additional mass force and not introducing added mass force in the calculation. The motion law of the solid phase and the velocity distribution of the mixture phase was compared under the two kinds of schemes. Then confirmed the diameter of particle that need to consider the additional mass force in calculation. When the particle diameter was larger than 5mm, the additional mass force had an effect on the particle velocity and slip velocity of solid-liquid phase.3. The unsteady flow of the centrifugal pump under different diameter of particles which considered the added mass force were calculated. The numerical simulation results of different particle diameter, different particle concentration and different volume flow were obtained. The internal flow characteristics under different working conditions and the wear rate of flow components changes with the solid phase parameters were researched. The results showed that the discrete phase concentration in impeller and volute were varied with different diameter. The discrete phase concentration in impeller was increased with the increase of diameter, the discrete phase concentration in volute was decreased with the increase of diameter. In the solid-liquid twophase flow pump the wear of impeller was more serious than that of the volute. The junction position of pressure surface and the hub in impeller outlet was the place that wore most seriously. The particles aggregation was also high in this position.