Airflow migration and dust distribution law during coal mine excavation

We investigate the impact of the distance between the air outlet and the working face on dust migration and distribution law during the advancement of coal mine tunneling, providing theoretical support and technical guidance for clean production at the mining face. A unsteady CFD model was used to systematically analyze the spatiotemporal evolution of dust migration under different air outlet distances. Simulation results show that two recirculation structures form within the roadway airflow. As the air outlet distance increases from 5 m to 15 m, the airflow diffusion distance on the return air side of the respiratory zone increases from 10.2 m to 17.41 m. Dust migration results indicate that, affected by the air outlet distance, a longer jet distance weakens the flow's ability to constrain dust, making dust more likely to disperse throughout the cross-section of the roadway; as the distance increases, dust concentration at 0 m increases, while dust concentration in the respiratory zone on the return air side at the far end of the roadway gradually decreases, and the contamination range also gradually reduces. The distance of the air outlet is a key factor affecting dust distribution and diffusion range; reasonably setting its position can optimize ventilation and reduce respiratory zone’s dust concentration. The research results have significant theoretical and practical implications for guiding dust control in mines and promoting clean production.