Research on an Ultrafine Water Mist Partition Multistage Dust Suppression System in Underground Excavation Tunnel

Abstract

A large amount of coal dust is produced in coal mine excavation, which has a serious impact on the working environment and health of underground workers. To address this problem, the spatial and temporal evolution process of coal dust in the excavation tunnel is analyzed via numerical simulation, and an ultrafine water mist partition multistage dust suppression system is developed. The results show that in the original ventilation mode, the air velocity within 5 m from the workface varies greatly, up to 17 m/s. When the airflow impacts the workface, it shifts to the return air side and gradually stabilizes below 2 m/s. Driven by airflow, coal dust gathers around the tunneling machine and diffuses to the rear of the tunnel, the speed increases first and then decreases, and the whole tunnel is filled in 40 s. Within 10 s, the water mist particles cover the whole tunnel at a high speed, capture and settle the coal dust particles, and prevent the further spread of coal dust. After application to the I030409 excavation workface in the Qipanjing Coal Mine, the average reduction efficiency for total dust and respirable dust in the tunnel reached 91.74% and 93.4%, respectively. Therefore, the system successfully achieves partitioning multilevel dust reduction.