Numerical simulation on the influence of gob permeability on distribution of air leakage flow field

摘要

In the coal mine industry, permeability is a key factor to air leakage in gob, its value and distribution influence greatly the distribution of air leakage. CFD is applied to simulate the distribution of air leakage in gob at various permeability magnitudes. Gob refers to a porous medium made from loose coal and collapsed stratum mixture. It shows that the quantity of air leakage and distribution of air velocity, three zones of spontaneous combustion vary largely under condition of different magnitude of permeability. The permeability in gob is seen to gradually reduce. It shows the quantity of air leakage is small and air velocity in waste is low, and spontaneous combustion zone is close to the working face. The graph of relation between distance and air leakage rate shows that spontaneous combustion zone in gob will disappear on account of the lack air leakage rate. Therefore, by mean of technological measure such as gob grouting technique, it can reduce the permeability of gob, raise diffusion resistance of airflow, decrease air leakage from working area, and ease the danger of the spontaneous combustion.