Experiment Research On The Velocity Of Solid And Liquid In A Solid-liquid Stirred Tank

Solid-liquid mixing as an important means of operation in daily life and industrial production plays an important role in accelerating the mixing and mass transfer between materials.At present,the research on solid-liquid mixing mainly focuses on the two-phase mixing with small particle size particles,and the research concentrates on the velocity and flow field of continuous phase.Due to the high requirements of experimental conditions and post-processing for the correlation analysis of particles,research of large particle mixing is relatively rare.In order to improve the understanding of solid-liquid mixing,this paper uses the experimental method to analyze and study the solid-liquid mixing situation of large particles at low Reynolds number level.In this paper,a certain ratio of sucrose-sodium chloride solution and 8mm quartz glass beads are used for refractive index matching,the flow situation in a 220mm square mixing tank with solid concentration ranging from 0%-8%is investigated by particle image velocity(PIV)technology,at Reynolds number of 1325,agitated by a PBT impeller.The fluid velocity and particle properties are studied;mixing characteristics at different solid concentrations are compared and analyzed.According to the experimental results,when the solid concentration ranges from 0%to 1%at 60�,the peak of velocity and turbulent kinetic energy are located between the impeller and the tank wall close to the tank wall.The characteristics of the velocity in the stirring tank and turbulence kinetic energy are not significantly affected by the addition of the particles.The average velocity and the root mean square velocity decrease about 5%,and the particles are concentrated at the bottom of the tank.The flow field between different phase angles is different.When the solid concentration goes from 0%to 8%,a large number of particles seriously affected the flow field within the tank,the fluid velocity and turbulence kinetic energy have a greater degree of attenuation,comparing 0%and 8%,velocity at vortex area decreases 12%,the turbulence kinetic energy decreases more than 40%.The particle distribution shows a clear upward trend at solid fraction of more than 1%,the particle distribution in the shooting area shows a whole increase at 8%.As the velocity vector of the fluid cannot pass through the particles,the vortex originally present in the pure liquid phase is seriously weakened,and the velocity vector in the transient flow field can further explain the effect of the particle on the flow field.Based on the experimental results of PIV,the numerical simulation of 0%and 1%with experimental conditions are carried out using the lattice Boltzmann method(LBM).The condition between the solid-liquid two-phase flow fields is further analyzed,and the simulation data is consistent with experimental result.