Effect of drill pipe rotation on gas-solid flow characteristics of negative pressure pneumatic conveying using CFD-DEM simulation

Abstract Pneumatic conveying theory is applied to the negative pressure sampling for the gas content determination in coal seams. Herein, we investigated the gas-solid flow in the drill pipe with different rotation speeds using CFD-DEM simulation. Consequently, we found that the speed of drill pipe rotation increased with an increase in the influence distance of the swirling flow and the tangential velocity of the gas flow, whereas the change in the axial velocity and static pressure was minimal. Of note, the swirling flow of particles was more apparent. Additionally, the suspended particles and the particle concentration in the drill pipe increased, while the number of particles entering the drill pipe decreased. Due to the drill pipe rotation, the actual particle flow rate and solid-gas ratio were less compared to the ideal value. The impact of drill pipe rotation on the conveying efficiency of particles showed an optimal value.