Numerical Simulation Of Coal Surface Temperature During Desorption Of Gas Bearing Coal

Coal and gas outburst is one of the serious natural disasters in coal mines,which has brought huge losses and casualties to the country and coal mining enterprises in terms of economy and the health of coal mine workers.The desorption characteristics of gas are an important factor in the reaction of coal and gas outburst.The temperature changes during the desorption process.By studying the temperature changes,not only can the characteristics of gas desorption be evaluated,but also the evolution of coal and gas outburst can be further understood.Therefore,it is of great significance to study the temperature change during desorption.This paper uses theoretical derivation,numerical simulation and on-site application to comprehensively analyze the temperature changes of the coal surface under different adsorption equilibrium pressures.The main contents and conclusions are as follows:(1)Theoretical analysis of the law of temperature change in the process of gas desorption under different adsorption equilibrium pressures shows that the temperature change of coal surface changes when the equilibrium pressure of gas adsorption is changed while the environmental conditions remain unchanged.When the pressure becomes larger,the content of gas adsorbed by the coal body increases,the amount of gas desorption increases during the desorption process,the temperature decreases by a greater extent,and the rate of temperature decrease also increases;(2)Based on Fick's law in the spherical coordinate system,a gas desorption and diffusion model is established,combined with a temperature fitting equation,a model of coal surface temperature-desorption amount under different adsorption equilibrium pressures is established and numerically solved.The result surface:coal body The surface temperature decreases with the increase of gas desorption time,and the range of coal body temperature change during gas desorption increases with the increase of adsorption equilibrium pressure,and the rate of temperature decrease also accelerates;(3)By comparing and analyzing the numerical calculation results with the experimental data,the law of temperature decrease of the coal body surface under the two methods is the same.The amplitude is larger than that obtained from the experiment,because the influence of factors such as noise during the experiment results in a smaller range of data changes;(4)The feasibility of using temperature changes to predict coal and gas outburst is verified by analyzing the index values of coal body temperature to predict coal and gas outburst;the results of using infrared thermal imager are studied,and the choice of infrared thermal imager is propo sed.The above research provides a basis for predicting coal and gas outburst using the coal surface temperature change index,and is of great significance for preventing coal and gas outburst.