Field Observation And Simulation Study On Dangerous Area Of Gas And Coal Spontaneous Combustion In Dongpan Coal Mine

In order to explore the impact of gas and coal spontaneous combustion composite disaster area in the goaf,this paper takes the 21219 working face of Dongpang Coal Mine as the background for research,takes the field observation and observation,consults the literature for theoretical analysis,builds the experimental platform for similar simulation experiments and adopts FLUENT simulation.The software carries out a numerical simulation to combine several methods to comprehensively study,mainly to analyze the variation of gas and oxygen migration in the goaf and the change of the concentration in the high drilling position,and the distribution of the spontaneous combustion of coal and the dangerous area of gas complex disaster..In order to reduce the composite disaster area in the goaf and minimize the gas concentration in the upper corner,simulate the position of the high borehole in the goaf to find the best high position of the borehole,which is the arrangement of the borehole in the actual work.Provide some theoretical basis.The contents and conclusions of the study are as follows:(1)The unit method is used to measure the air leakage and the amount of gas emission from the working face.The air volume leaking into the goaf in the first half is413m~3/min,and the air volume leaking into the working surface in the second half is296 m~3/min.The air leakage is 117 m~3/min.The gas concentration of the working face increases as a whole in the direction of the tendency,but the gas concentration in a certain range will decrease under the influence of the high-level drilling and the gas concentration outside the influence range along the direction will continue to increase.The measuring points are arranged in the goaf,and the collected measuring point gases are analyzed and studied.It is concluded that the range and distance affected by the high-level drilling and buried pipe extraction are about 60 meters.The oxygen concentration is continuously decreasing as the working surface advances,and reaches a stable state in the depth of the goaf.(2)Using the similarity theory and the derived parameters to establish a flow field experimental bench in the goaf.The similar simulation experiment was carried out by using the three-dimensional flow field test bench of the goaf,and the measured gas and oxygen concentration were plotted by MATLAB software,and the gas concentratio n distribution contour map and contour map and the oxygen concentration distribut io n cloud map and equivalent were obtained.Line graph,analyzing the variation of gas and oxygen concentration.At the same time,the change of the position of the high-le ve l drilling hole has a certain influence on the air leakage in the goaf.The effect is that the farther the air leakage from the return air passage is larger,it is not conducive to the air leakage in the gob area to exclude the gas on the return air side.(3)Using FLUENT simulation software to simulate the gas and oxygen migrat io n rules in the high-level borehole goaf from different levels of the return airway,and to compare and analyze the composite disaster danger zone in the simulation results.It is concluded that in the high-level borehole,the composite disaster area of the goaf in the goaf is in different positions,and the size of the composite disaster hazard area is compared to determine the optimal high-level drilling arrangement position.