The Influence Of Material Propertyies On Flow And Suspension Characteristics In A Solid-Liquid Stirred Tank

Solid-liquid suspension is one of the most common processes inmixing. It is significant to measure solid and liquid velocities in a stirredtank for industrial manufacturing. Because the actual materials aredifferent, the local liquid velocities and its distribution are varying withthe solid particles and liquid viscosity changing, which will directly affectthe suspension state in stirred tank. Therefore, it is meaningful to studythe influence of material properties in solid-liquid mixing tank forindustrial production.The local liquid velocities were measured by a bi-electrode electricconductivity probe in a solid-liquid suspension system. The experimentalinvestigation was carried out in a full baffled, flat bottom, cylindricalvessel, with 476 mm diameter, equipped with a new type propeller(CBYⅢ) to push the water downward. The resin particles andglassed-beads with the average diameters of which were 0.465mm,0.605mm, 0.865mm(ρ_p=1300kg/m~3), 0.1mm, 0.405mm, 0.525mm and 0.75mm(ρ_p=2500kg/m~3) respectively were chosen as the dispersed phase.The particle volumetric concentration changed from 2.5% to 20%.With the different diameter, density and volumetric concentration ofthe solid particle, the just-suspended agitated speed was measuredthrough finding the moving of particle at the bottom to explore the effectof the above-mentioned factors.The local liquid velocities were measured in the wall region withsolid volumetric concentration changing from 2.5% to 15%, and thevariety of liquid velocity distribution was studied by adding the differentdiameters and densitiesparticles. With the different diameter, density andvolumetric concentration of the solid particle, the local liquid velocitieswere discussed. According to the results, shear rate and circulation flowwere calculated by adding solid particles with different diameter anddensity, the influences of mixing efficiency and pumping capacity werealso discussed primarily. The results showed that shear rate andcirculation flow were not significantly affected by the diameter anddensity of solid particles.At the same time, based on the function provided by the commercialCFD code (CFX 5.5.1), the local liquid velocities of the wall region weresimulated in the stirred tank. By contrast with the experimental data, theresults obtained from numerically simulating are in good agreement withexperimental data.