Field measurement and numerical simulation of dust generation and movement regularities in coal mine drilling holes

In order to effectively improve the dust control effect of dry drilling hole in coal mines and further improve the working environment at the coal mine drilling site, a research method combining on-site measurement and numerical simulation is adopted. Taking the measured dust generation intensity and particle size distribution of the drilling hole dust source as input parameters, numerical simulation and in-depth insight analysis are carried out on the generation, movement and settlement regularities of the dust in dry drilling hole of coal seams. Moreover, the spatial distribution characteristics of the dust concentration in the drilling field are explored to provide a scientific basis and technical guidance for the research and development of the dust control device for coal seam drilling holes. Through the research, it is found that: after the dust particles are generated at the bottom of the hole, they are spirally and rapidly ejected from the hole mouth under the entrainment of the compressed air. Under the dual effects of the obstruction of the roadway wall surface and the carrying of the roadway air flow, the dust particles diffuse with the air flow and randomly pulsate transversely. During the dust settlement process, the larger the dust particles are, the shorter the time required for them to settle to the ground is, and the closer the diffusion distance with the air flow is. Within the conical distribution area of the drilling hole, the dust concentration gradually decreases along the direction of the drilling axis, and the coverage range gradually increases. Within the distribution area along the roadway, the dust concentration in the x-axis direction first increases rapidly and then gradually decreases slowly. The dust concentration in the machine lane in the y-axis direction is generally higher than that in the sidewalk. In the z-axis direction, the dust concentration gradually decreases from the height of the drilling hole to both the upper and lower sides.