Numerical study of gas-solid two-phase flow in a coal roadway after blasting

Abstract

The coal roadway heading using a blasting method is very common in China. However, the coal dust produced by blasting is the most serious problem in a roadway of coal mine. The gas-solid two-phase flow regularity for blasting heading face is the key scientific issue for dust control. In this paper, a real blasting heading face in China was taken as the physical model and a method coupling a direct simulation Monte Carlo (DSMC) scheme with a CFD software was adopted to study the properties of dust particles (0.1-100. µm in diameter) in the flow field of a roadway after blasting. The results show that dust group produced from the heading face is jetted into the roadway under the shock wave after blasting, and is diluted from its back-end to the front-end by the airflow from the pressing pipe arranged around the heading face, then dust concentration shows an overall gradual decrease, and finally the respirable dust particles exhibit an alternant thin dense phase distribution in the roadway, whereas other dust particles (>5. µm in diameter) spread at the bottom of the roadway and form dust retention. The dust concentration in the front-end of the roadway around the heading face is always higher than that in other zones due to the existence of vortex region. The respirable dust concentration is slightly greater than the standard of air quality in the beginning, and quickly reaches the standard. But the total dust concentration always does not meet the standard of air quality in general. The simulation results are also verified by the field data. The research results are helpful for providing more suitable guidance for the dust control.