Research On Numerical Simulation Of Airflow Distribution In Gob

Air leakage from coal mining face to gob has great influence on gas distribution and emission as well as spontaneous combustion in waste. Permeability is a key factor to air leakage, its value and distribution influences greatly the distribution of air leakage. The mechanized support influence air leakage from working face to gob.According to the percolation theory of porous media, computational fluid dynamics software Fluent is applied respectively to simulate the distribution of air leakage in gob at various supposes of permeability distribution, permeability magnitude and mechanized support. The paper analyses the influence factors on leakage flow field solution, such as gob permeability and fully mechanized support. It shows that the quantity of air leakage and distribution of air velocity, three zones of spontaneous combustion vary largely under condition of different distributions of permeability, that is, continuous distribution, three uniform distribution zones and one even distribution zone. When gob permeability is one even distribution zone, quantity of air leakage is small and spontaneous combustion zone is close to the working face. In case of dividing the gob into three zones, in each zone the permeability distributing uniformly, it leads that the air leakage velocity jump at the boundary of zones because the permeability distribution is not continuous. When working face has mechanized support, air leakage quantity is small, velocity is low in goaf, and spontaneous combustion zone is more approach to working face. Therefore, distribution of permeability and mechanized support should be considered carefully as precise as possible in order to get the distribution in gob.