Simulation Of Gas Flow In Underground Coal Seam Based On LBM

To simulate gas flow and study its rule will have practical significance for preventing gas accidents,improving work environment,developing and utilizing methane.This paper,on the basis of previous research,uses the Lattice Boltzmann Method to study the gas seepage,gas drainage,gas emission and gas outburst.Firstly, this paper introduces the multi-distributed Lattice Boltzmann method(LBM)-velocity, temperature and concentration gradient which in accordance with the equation of gas flow(Darcy-Law) in coal and turbulent gas flow in working face.Also introduces the bounce-back and curved boundary treatments of LBM.Secondly,this paper established the dynamic LBM model for gas seepage and gas drainage which takes account into the adsorption and porosity properties of coal impact of gas seepage.And simulate the two-dimensional and three-dimensional process of gas seepage in single coal seam.Also we study the effects of porosity on the velocity and concentration of gas seepage.Later,we use the LBM of gas transport with the ventilation system of model U to establish the dynamic LBM model of gas emission.At the same time,in order to improve computational efficiency and ease to computer implementation we apply to the domain decomposition method,so we divide to two sub-blocks,one is gas seepage in coal seam, another is gas transport in working face.And the simulation results demonstrate that we can see clearly the gas distribution in working face after gas emitting and can get the rule of gas emission in working face.At last,we established the dynamic LBM model for gas outburst which takes account into the in-situ stress and gas pressure impact of gas outburst and permeability.Also consider the temperature change in outburst.And the simulation results demonstrate that we can see clearly the distribution of gas concentration,temperature and velocity in working face after gas outburst.This paper focuses on gas seepage,gas emission and gas outburst in coal seam.This subject has great social and economic benefits and profound realistic significance.It will not only directs the industrial production and makes effective measures for gas control, prevents serious gas accidents,and gives full play to the totally mechanized coal mining, but also provides a new method in further studying of coupling theory between coal and gas, outburst mechanism of gas and gas drainage.