Research on the dust reduction by spraying law of fully mechanized face using a large-scale dust and droplet coupling model

To effectively reduce the dust pollution in the fully mechanized face, this study proposes a large-scale dustdroplet coupling model based on LES-VOF and the dust-droplet probabilistic collision algorithm. Subsequently, the dispersion of droplets and dust under various spray pressures was analyzed. The accuracy of the model was verified through experiments and measurements, with a relative error of less than 15.0%. The analysis results indicated that the airflow on the air inlet side generated a vortex field, resulting in the accumulation of dust and droplets within 0-9.8 m from the heading face. The airflow on the air outlet side moved backward along the tunnel floor, causing the droplets and dust to disperse in a larger area. As the spray pressure increased, the droplet coverage distance showed a bimodal pattern, while the dust diffusion distance initially increased and then decreased. If the spray pressure exceeded 5 MPa, the covering distance of droplets and dust reached 23.0 m and 4.2 m, respectively, and the dust concentration in the area going beyond 15.0 m was below 20.0 mg/m3. The dust concentration at the driver's location was measured at 5.35 mg/m3, achieving a significant dust reduction rate of 90.60%. More importantly, the on-site application analysis has presented well-aligned data with the simulation results.