Research on an ultrafine water mist partition multistage dust suppression system in underground excavation tunnel

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. For this problem, through numerical simulation to understand the temporal and spatial evolution law of coal dust in the excavation tunnel, that is, the coal dust velocity first increases and then decreases along the diffusion direction, and the maximum velocity reaches 8 m/s, and fills the entire tunnel at 50 s. In this regard, the an ultrafine water mist partition multistage dust suppression system was proposed, and numerical simulation studies were carried out on the wind flow distribution and water mist particle transportation law, and the results showed that the air flow velocity in the 0-5 m area was between 6-14 m/s and varied a lot, and the speed of the spray jet in the 10-30 m area decayed faster, and eventually stabilized at 1 m/s. The water mist particles surrounded the cutting head with a speed of 8 m/s in 2 s, and spread to the working face. After 10 s, the water mist particles cover the whole roadway, and the speed is also stabilized at 2 m/s. Through field application and measurement in the I030409 excavation face of Qipanjing Coal Mine, the average reduction efficiency for total dust and respirable dust in the tunnel reached 91.74% and 93.4%, respectively, which effectively controls the problem of dust pollution in the excavation tunnel.