Abstract:
The shearer in a fully mechanized mining face generates significant turbulent airflow during coal cutting, resulting in changes in airflow velocity in the mining area and causing the lateral dispersion of coal dust particles toward pavements. To investigate the effect of cutting-induced turbulent airflow on the lateral dispersion of coal dust, the Multiple Reference Frame (MRF) model was applied to simulate drum rotation during coal cutting. Numerical simulations were conducted to analyze the coupled transport patterns of airflow and coal dust under different coal cutting conditions, revealing the relationship between airflow distribution and coal dust concentration distribution in the mining face. To reduce the impact of cutting-induced turbulent airflow on the lateral dispersion of coal dust, a dust source tracking and spray dust suppression system for the shearer was proposed. The system formed a mist curtain between the shearer drum and the pavements using spray devices installed on the canopy or the front cantilever beam of the support. It effectively mitigated the disturbance caused by turbulent airflow, prevented the lateral dispersion of coal dust particles, and enabled dynamic tracking of the dust source generated by drum cutting. The simulation results showed that the turbulent airflow generated by drum rotation under different cutting conditions caused airflow to shift laterally toward the pavements. When the drum rotation speed reached 29.29 r/min and the system airflow velocity was 1.40 m/s, the lateral velocity shift exceeded 0.54 m/s, causing coal dust particles to diffuse into the pavements and resulting in coal dust concentrations exceeding 300 mg/m
3. This phenomenon was particularly pronounced during downwind coal cutting, where the coal dust concentration in the pedestrian area reached 385.12 mg/m
3. Field test results indicated that the dust source tracking and spray dust suppression technology for the shearer achieved a dust suppression efficiency of 83.68%, while the standby power consumption of a single spray point remained below 10 W.