Effect of the particle shape and swirling intensity on the breakage of lump coal particle in pneumatic conveying

This work studied the influence of the particle shape and flow regime on the lump coal breakage in pneumatic conveying using CFD-DEM simulation. A variety of agglomerates with different sphericities were modelled by the parallel bond method to analyse the breakage characteristics of lump coal. The numerical parameters, simulation conditions and CFD-DEM simulation results were separately validated by experimentation. To demonstrate the lump coal breakage process, the mechanism energy variation in the coal agglomerate was analysed. The fragmentation degree of the coal agglomerate was positively correlated with the energy difference in collision. The integrality ratio of the coal agglomerate increased with the particle sphericity and swirling number in pneumatic conveying. A quasi-periodical downgrade in the coal agglomerate integrality ratio was shown in the swirling flow. A remarkable improvement in the coal agglomerate integrality ratio from approximately 0.85 to 0.975 was observed in swirling flow pneumatic conveying. The regression relationship of the particle sphericity and swirling number fit the Exp3p2 exponential function well. [Display omitted] •Obtained a real morphology of lump coal agglomerate by parallel bond model•Analysed the coal agglomerate breakage in sight of mechanism energy variation•A quasi-periodic integrality ratio downgrade was shown in the swirling flow.•The integrality ratio increased with particle sphericity and swirling number.•Exponential function fits particle shape and swirling intensity influence well.