CFD simulation of the mixing and dispersing of floating particles in a viscous system

Based on the Gidaspow model, the distributions of velocity, turbulence intensity, and solid concentration in stirred vessels equipped with a down-pumping propeller (TXL),a six flat-blade disc turbine (Rushton), or a down-pumping six 45° pitched-blade turbine (PBTD-6) in a viscous system were simulated. The power curve of the TXL propeller and the dimensionless solid concentrations of one sampling point in the vessel at different agitation speeds were obtained by simulation and experiment, which were in good agreement with each other. The results showed that: (1) both the tangential velocity and turbulence intensity on the liquid surface caused by a Rushton turbine were the highest of the three conditions at the same agitation speed; (2) the turbulence intensity on the azimuth of 90° behind the baffle near the shaft on the liquid surface was relatively larger than that in other regions; (3) the uniformity of solid concentration distribution in the stirred vessel equipped with a Rushton or PBTD-6 turbine was better than that with a TXL impeller at the same agitation speed.