Research on the dust transportation law and cyclone air curtain dust control technology of coalface.

Abstract

This study investigates the large-scale dust accumulation caused by improper airflow in a coal mine roadway with mixed ventilation, aiming to understand dust distribution patterns and reduce dust concentration. A simple model was developed using SpaceClaim, and numerical simulations were performed using Ansys Fluent. The results revealed that dust filled the entire tunnel, with significant accumulation at the driver's position and the corner of the return air side. To improve the hybrid ventilation system, radial outlets were added to the inlet duct to create a vertical air curtain that intercepts dust diffusion. This air curtain, in combination with the exhaust outlet, formed a cyclone airflow moving toward the excavation face, actively reducing dust levels. Four key factors affecting dust concentration in the pedestrian breathing zone and driver's position were optimized using both single-factor and multi-factor integrated control, based on the Box-Behnken design. The optimization results indicated that the optimal dust control configuration included a guide channel width of 0.04 m, a height of 0.09 m, an axial-to-radial airflow ratio of 0.5 for the inlet duct, and an exhaust duct diameter of 1.2 m. After optimization, dust concentration in the pedestrian breathing zone decreased by 63.6%, from 1.19 × 10⁻⁴ kg/m³ to 4.33 × 10⁻⁵ kg/m³, and the dust concentration at the driver's position decreased by 78.2%, from 1.78 × 10⁻⁴ kg/m³ to 3.85 × 10⁻⁵ kg/m³. The factors influencing dust concentration in the pedestrian breathing zone, ranked by significance, were the axial-to-radial airflow ratio, duct diameter, guide channel width, and guide channel height. For the driver's position, the order of importance was axial-to-radial airflow ratio, guide channel height, guide channel width, and duct diameter. Finally, based on the similarity principle, an appropriately scaled experimental model was constructed for ventilation and dust control. The optimized airflow regulation plan was tested in air curtain dust control experiments, with results that closely matched the numerical simulations, showing an error of less than 5%.