A study of the spray atomization and suppression of tunnel dust pollution based on a CFD-based simulation

Abstract

In order to solve the problem of severe dust pollution in a tunnel during continuous mining effectively, this study used the external spraying method around a continuous miner and determined the optimal parameter settings via an experimental analysis, numerical simulation and field measurement. According to the experimental results, the optimal nozzle was firstly determined as a round-mouth nozzle with an X-type diversion core with a caliber of 2.4 mm (hereinafter the X-2.4 mm nozzle). Next, the numerical simulation results confirmed that the cutting head can be fully wrapped when the nozzle was installed at an outward inclination angle of 15°. At a spray pressure of 7 MPa, the formed spray field was almost unaffected by the airflow and could cover the dust-producing region fully, thereby achieving an effective dust settling process. Finally, the proposed external spraying technique was applied to the No.104 continuous mining face of the Jinjitan Coal Mine, Shanxi, China. Under optimal spraying conditions, the dust-suppression efficiency in the continuous mining face exceeded 90%, and the concentrations of respiratory dust at the tail of the scraper and at the driver’s operating position were 6.2 mg/m3 and 10.1 mg/m3 respectively. Therefore, the proposed solution can solve the problem of dust pollution in a tunnel effectively.