K.W. Chu

Numerical study of the effect of vortex finder configuration in dense medium cyclones

A mathematical model is proposed to describe the multiphase flow in a 1000 mm industrial dense medium cyclone (DMC). In this model, a Mixture Multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite contaminated with non‐magnetic material in water) and the air core, where the turbulence is described by the well established Reynolds Stress Model. The stochastic Lagrangian Particle Tracking model is used to simulate the flow of coal particles. The proposed approach is qualitatively validated using literature and industrial data and then used to study the effect of the vortex finder configuration including the vortex finder length and diameter. The results show that the operational head, density differential and the medium split reporting to overflow increase to a maximum and then decrease as the vortex finder length increases. Because of the effect of the short circuit flow, the vortex finder in DMC cannot be too short or too long. As the vortex finder diamet...

Discrete Particle Simulation of Gas‐solid Flow in a Cyclone Separator

Gas cyclones are widely used in industries to separate solids from gas stream. It is well known that solids loading will significantly affect the performance of gas cyclones. In this work, a numerical study of the gas‐solid flow in a gas cyclone at different solid loadings is carried out by means of Combined Continuum and Discrete Method (CCDM). In the CCDM, the motion of discrete particles is obtained by Discrete Element Method (DEM) which applies Newton’s laws of motion to every particle and the flow of continuum fluid is described by the local averaged Navier‐Stokes equations that can be solved by the traditional Computational Fluid Dynamics (CFD). The model successfully generated the strands flow pattern of solids that is typical in gas cyclones. The simulated pressure drop under different solid loadings agreed with experimental measurement quantitatively. It is predicted that the reaction force of solids on gas phase caused the decrease of the tangential velocity of gas phase and thus the decrease of...