Numerical simulation of behavior of fine coal in oscillating flows

A mathematical Euler/Lagrangian model based on computational fluid dynamics (CFD) approach is used to simulate the stratification of coal particles in the column jig. Interactions of wide size range and density distributing particles with the fluid have been simulated in the oscillating flow. Fluid motion is calculated by directly solving the Navier–Stokes equations by a SIMPLE approach. Particles are moved in a Lagrangian frame through the action of forces imposed by the fluid and gravity. The magnitude of forces acting on particles has been analyzed and compared. Particle effects on fluid motion are fed back at each time step through calculating the velocity disturbance caused by the particle. Particle–particle and particle–wall collisions are also considered. The simulation captures the essential features of jigging process. It was found that the pulsating amplitude has less effect on stratification on fine particles than frequency does in the jigging. The best stratification is also achieved at some intermediate values of amplitudes and frequencies.