Numerical Simulation Of Spontaneous Combustion In Goaf With Multiple Air Leakage Paths

Most of the mines in China enter deep mining,the resulting goaf areas are bound to communicate with the original goaf and abandoned roadways,forming multiple air leakage paths.Meanwhile,the negative pressure of gas extraction disturbs the gas flow field in the mined-out areas,increasing the possibility of spontaneous combustion of mined-out abandoned coal,making it more difficult to prevent and control spontaneous combustion of mined-out abandoned coal.Therefore,it is very necessary to study the law of spontaneous combustion in goaf with multiple air leakage paths.First of all,through the analysis of air leakage in the goaf area,obtained the influence factors of coal spontaneous combustion,the influence on coal spontaneous combustion of goal air leakage were analyzed: mainly by the change of goaf spontaneous combustion "three zones" as impact index,oxygen concentration as the index of goaf spontaneous combustion "three zones" division standard.Second coal spontaneous combustion characteristic is studied through laboratory experiments,and to provide parameters for numerical simulation,combined with the actual situation of the mine working face,to monitor the underground tube,the measured data and the corresponding numerical simulation results were analyzed,determine the rationality of the numerical simulation.Finally using FLUENT software to establish the mathematical model of goaf,according to relationship between mine goaf and the location of the adjacent goaf air leakage situation,more than in the adjacent area set up air leakage passage,numerical simulation was made for the mined-out area is divided into six stages.The distribution of oxygen concentration field in goaf with multiple air leakage paths without gas extraction and gas extraction is simulated,the danger area of spontaneous combustion in goaf with multiple air leakage paths is divided.Research results show that the mined-out area and adjacent goaf air leakage passage between the goaf of the oxidation zone will increase,thereby increasing the possibility of goaf coal spontaneous combustion,along with working face advancing,more air leakage passage goaf oxidation zone width increase gradually,increase gas extraction goaf air leakage at the same time,thereby increasing the width of the oxidation zone.The reasonable length of buried pipe extraction in each section of goaf is selected by comparative analysis.The research of the paper provides an important reference for reducing the spontaneous combustion of abandoned coal in goaf in the process of deep mining.Figure 51;Table 16;Reference 59...