The determination of the minimum agitation speed, Njs, to achieve the just-suspended off-bottom solid suspension state in liquids in stirred vessels is an issue of significant importance in industrial processes. Here, Njs was computationally predicted for a stirred, fully baffled vessel provided with different axial or radial impellers using an LBM-based CFD model coupled with a novel method to extract Njs from the computational results. Accordingly, the number of solid particles in a very thin control volume near the bottom of the vessel were computationally predicted over a range of agitation speeds, N, to determine the mass fraction of suspended solids, Xm. A regression analysis based on the logistic equation was then applied to the Xm-N curves and a simple, derivative-based mathematical method was applied to predict Njs. The results obtained with this novel computational approach were found to be in good agreement with previous experimental data.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering
- Computational Fluid Dynamics (CFD)
- Large Eddy Simulation
- Logistic Equation
- Solid suspension