CFD modelling of nitrogen injection in a longwall gob area.

This paper describes computational fluid dynamics (CFD) simulations conducted to investigate the effectiveness of N2 injection in an active panel and a sealed longwall gob area to prevent and suppress spontaneous heating of coal using various injection locations and flow rates. In the active panel simulations, a single longwall panel with a bleederless ventilation system was simulated. The spontaneous heating of crushed coal from pillars was simulated and N2 was injected from different locations on the headgate side and through boreholes from the surface. The N2 injection rate at each location was varied between 0.18 m3/s and 0.94 m3/s (380 and 2000 cfm). In the sealed longwall simulations, seal leakage rate was varied to determine its effect on N2 injection effectiveness. The results of this study should aid mine ventilation engineers in developing more effective N2 injection strategies to prevent and control spontaneous heating of coal in underground coal mines.