Research on numerical simulation for the transport law of multi-component dust in roadway blasting

Mine dust has the characteristics of high concentration, slow diffusion, wide particle size distribution range and long retention time. The long excavation of a main roadway is taken as the research object, the fluid simulation software of ANSYS FLUENT is utilized, the model of gas-solid multiphase flow, blasting chemical reaction, and material transport are employed to simulate the influence of pressure waves on the transport and dispersion of multi-component particle size dust in the roadway after instantaneous blasting. The obtained results are as follows: ①there exist two stages of mixing and separation for dust particles in the roadway after blasting. Dust with small particle sizes exhibits higher movement speeds compared to larger particles, resulting in stratification. Small particle size dust tends to concentrate at the vault of the roadway, while large particle size dust accumulates at its arch. ②Initially, respirable dust mainly gathers at approximately 1/7-1/8 of the length along the roadway. However, during later stages, peak dispersion shifts towards exit position until it becomes evenly dispersed throughout. ③The average velocity across sections fluctuates periodically of dust particles but sharply decreases after reaching a certain distance. Additionally, peak velocity distribution continuously decreases over time. ④At the height of the breathing zone, the dust concentration along the roadway shows a rapid-steady decline trend, and the peak concentration is near the palm surface. The research results can provide reference for timely and efficient prevention and control of mine dust, realize green and safe mining and reduce occupational diseases.