Numerical simulation and experiment of coal particles separation in flexible air chamber jig.

[Display omitted] • VOF-DEM model was proved to be suitable for the coupled calculation of liquid and solid phases in jig separation. • Gas cycle in fluid-particle systems affected the pulsation, looseness, and separation of particles. • Reasonable gas working cycle was obtained for jig separation of clean coal and middling coal. Flexible air chamber jig is a new type of coal sorting and processing equipment with broad application prospects. The separation of coal particles in the jig mainly depended on the gas working cycle, liquid level height and particles looseness. This paper discusses the separation of clean coal and middling coal in this jig with simulation and experimental methods. Numerical simulation of jigger separation process was realized, and the effects of inlet, expansion and exhaust proportion on the water movement and particle separation were investigated based on the liquid level height, bed looseness and percentage of particles. It was verified by the water level detection experiments. The results showed that the model was accurate and the experimental results were consistent with the simulation. The maximum discrepancy between the water levels in the experiment and the simulation was less than 5%, confirming the accuracy of the VOF-DEM (Volume of Fluid-Discrete Element Method) model. The liquid level was significantly affected by the gas working cycles, while the bed looseness was mainly affected by the intake proportion. Appropriate intake and exhaust proportions increased the proportion of particles with different densities. A reasonable gas working period proportion for jigging separation: intake 24%, expansion 27%, and exhaust 24%. In this condition, the proportions of Zone 1′s clean coal and Zone 2′s medium coal is 81.16% and 94.18%, respectively. [ABSTRACT FROM AUTHOR]