Effects Of The Air-flow Direction On The Distribution And Accumulation Of The Gas In The Inclined Coalmine Tunnel

Based on the foundational theory of Computational Fluid Dynamics, the influence of velocity inlet and outlet to velocity field in airway with through airflow has been studied by Fluent,a Computational Fluid Dynamics software. The affect of turbulence energy k and dissipation rateεon simulation results of airflow field in roadway with through airflow is investigated. to which the SIMPLEC (Semi-Implicit Method for Pressure-Linked Equations Consistent) algorithm procedure has been applied to get the numerical value of the given field. In addition, the standard wall function is also used to deal with the airflow by the tunnel wall. In so doing, we have obtained the air-flow distributions in the airway by using a standard k ?ε?t?he two equations turbulence model in the full turbulent area. The simulation results fit well with the theoretical one and the model experiment data. The mass transfer equation to describe the methane emission on roadway surface is studied on the basis of study of airflow. The effects of the air-flow direction on the distribution and accumulation of the gas in the inclined coalmine tunnel was simulated.As a result of the numerical simulation, the tunnel gas is likely to get accumulated or easily congested at the top of the two sides of the airway, with its concentration remaining near the roof of the tunnel. Moreover, the gas and the airflow tend to get more easily mixed with the increase of the airflow speed and the tunnel inclination upwardly instead of forwardly. However, in case of downward ventilation, there would appear a remarkable adverse gas movement tendency particularly in the condition when the airflow speed is rather small. Nevertheless, the distance of the gas reverse current could be shortened if the airflow speed is turning stronger. the location of gas emission has a great influence on gas distribution at roadway. The gas released from roof of the roadway is difficult to mix with the airflow and easy to accumulate near the roof. The gas concentration near roof and sidewalls of the roadway are high when gas is released from sidewalls of the roadway. The methane emitted from the floor is easy to mix with the airflow bucause of buoyant effect and the tendency of methane moving upward.