Numerical Simulation Study of the Optimal Parameters for Dust Reduction by an External Air Curtain (EAC) in Continuous Mining Tunnel.

Coal dust in continuous mining tunnels is extremely hazardous to drivers and other workers. In order to solve this problem, a continuous mining tunnel model is built based on computational fluid dynamics and gas–solid two-phase flow theory. Fluent 19.2 software is used to analyze the effects of air pipe outlet location (d) and external air curtain (EAC) outlet air velocity (vvent) on dust dispersion. The effects on the characteristics of dust dispersion are analyzed separately, and it is concluded that d=7 m is optimal. At this distance, the average dust concentration at the breathing zone height is low, and there is no significant fluctuation or rebound in the dust concentration during the dispersion process. When vvent=6 m/s , the highest dust separation efficiency of 89.3% occurs at a breathing height of y=1.6 m and x=5.82 m (133 mg/m3). The driver's position is protected with a dust separation efficiency of 79.2%. As the vvent value increases, the dust separation efficiency increases slowly. The cost of generating airflow should be considered for dust reduction efficiency, and an optimal vvent of 6 m/s is recommended. The findings of this study can provide a theoretical basis for the selection of ventilation parameters for air curtain dust reduction in continuous mining tunnels with rectangular cross section. [ABSTRACT FROM AUTHOR]