Numerical Simulation Of Goaf Spontaneous Combustion Characteristics Under Extraction Conditions

Gas extraction technology in goaf is one of the technical means to control gas in mine.However,in the process of goaf extraction,the existence of negative pressure will increase the air leakage in the goaf and increase the risk of spontaneous combustion of residual coal in the goaf,which directly affects the law of spontaneous combustion of coal in the goaf.Therefore,it is of great significance to study the spontaneous combustion characteristics of coal in goaf under different extraction conditionsOn the basis of the theoretical research on coal mechanism,gas extraction technology and the classification of three zones of spontaneous combustion in goaf,the related parameters of simulation were obtained by using laboratory experiment.Then the mathematical models of temperature field and oxygen concentration field in goaf were established,and the gas extraction process parameters were determined by COMSOL simulation software.On the premise that other parameters remain unchanged,the effect of different suction negative pressure conditions on spontaneous combustion in goaf is simulated.Finally,the safety technical measures of goaf are put forward.The conclusion shows that the length of buried pipe is 30 m,the radius of buried pipe mouth is 120 mm.With the increase of suction negative pressure,the width of spontaneous combustion zone of air inlet roadway in goaf gradually widens,and the change of negative pressure value is more obvious.The width of spontaneous combustion zone of air return roadway first increases and then decreases.The high-temperature area increases gradually with the increase of negative pressure,and the high-temperature area spreads continuously to the side of the return air lane.The higher the negative pressure is,the faster the diffusion rate will be.The air leakage velocity in the goaf increases with the increase of negative pressure,and the flow is continuously converging to one end of the buried pipe mouth.It has certain theoretical significance to optimize the extraction technology.Figure 30;Table 5;Reference 56...