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

Abstract

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 downpumping 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.

Effect of impellers on particle mixing behaviour in KR desulphurization process

“…The Euler-Euler approach is adopted to simulate the stirring process, and the Realizable k − 1 model with a strong ability to correct the rotating flow is used to calculate the turbulence flow. The solid-liquid phase mass and momentum balance equations are expressed as follows [20]:…”

“…The Euler–Euler approach is adopted to simulate the stirring process, and the Realizable model with a strong ability to correct the rotating flow is used to calculate the turbulence flow. The solid–liquid phase mass and momentum balance equations are expressed as follows [20]: where, , , , , , , and are the density, volume fraction, velocity vector, pressure, gravitational acceleration, tensor of shear stress, bulk viscosity, and inter-phase force of liquid phase and solid phase , respectively. is the effective viscosity, for the liquid phase, , for the solid phase, .…”