To address the problems that the dust pollution law dominated by air distribution volume in coal mining faces is unclear, the key influencing factors of the wind resistance performance of spray are unknown, and the mechanism of environmental airflow on dust-fog coupling is not explicit, this study takes the 3217 working face of Shanxi Tiandi Wangpo Coal Mine as the research object. By combining numerical simulation with field and laboratory tests, numerical simulations were carried out on the airflow distribution and dust migration trajectory of the working face under different air distribution volumes, as well as the droplet migration trajectory and dust-fog collision behavior under the disturbance of environmental airflow. The wind resistance performance of different types of nozzles was tested, a dust control system was constructed, and the dust reduction effect of the system was verified via field tests. The influence of air distribution volume on airflow and dust migration was revealed, the key factors affecting the wind resistance of high-pressure and pneumatic sprays were clarified, the mesoscopic dynamic behavior of dust-fog coupling under environmental airflow disturbance was uncovered, and the optimal nozzle type was selected to build the dust control system. The results show that air distribution volume significantly regulates the airflow distribution and dust migration characteristics of the working face. Under low air distribution volume, the wind speed is high on both the inlet and return air sides of the shearer; under medium air distribution volume, the wind speed on the inlet air side of the shearer is higher than that on the return air side; under high air distribution volume, the wind speed on the return air side of the shearer is higher than that on the inlet air side. With the increase of air distribution volume, the dust migration distance, dust concentration and particle size range in the return airway increase. The dominant factor for the wind resistance of high-pressure spray is droplet size, while that of pneumatic spray is initial injection velocity; the high-pressure flat-head conical nozzle exhibits the optimal wind resistance performance. Dust wettability is positively correlated with dust-fog collision velocity, and the wettability reaches the maximum at a collision velocity of 11 m/s.After field application of the dust control system constructed based on this research, the dust reduction efficiency in key areas all exceeds 80%, and the highest dust reduction efficiency at the center of the return airway section reaches 90.77%. The research results provide key theoretical basis and technical support for efficient dust control in underground coal mining faces, and have important practical significance for ensuring the occupational health of operating personnel.
Hongjie et al. (Thu,) studied this question.