Study On The Variation Of Surface Temperature Of Gas-containing Coal Under Uniaxial Loading

In order to provide a theoretical basis for the prediction of coal and gas outburst and other disasters in the coal mine by using the temperature parameters of coal body,this paper designs an experiment to measure the change of infrared radiation temperature of coal sample in the process of uniaxial loading by using the infrared radiation thermometer.Based on the theory of rock mechanics,gas seepage mechanics,thermodynamics and other disciplines,the experiment is analyzed in this paper,the coupled mathematical model of gas bearing coal is established,and the process of gas-containing coal loading in uniaxial is simulated by COMSOL Multiphysics software,and the law of coal body temperature change is obtained.By comparing the experimental results with the corresponding simulation results,it is found that when the initial gas pressure in coal is 0.1MPa,the experimental results are in good agreement with the simulation results,which verifies the correctness of the established model to a certain extent.At the same time,on the basis of the model,other factors that may affect the temperature change of coal are simulated and analyzed,mainly including the initial gas pressure in gas bearing coal and the young’s modulus of coal and the initial porosity of coal.1)With the increase of the initial gas pressure in the gas bearing coal,the surface temperature of the coal body generally shows a downward trend.When the gas pressure is0.1MPa,the temperature curve shows an upward trend and increases at most to about 0.2℃;when the gas pressure is between 0.2MPa and 0.5MPa,the temperature curve first decreases and then increases,but the final result still drops;when the gas pressure is greater than0.5MPa,the temperature curve continues to drop.When the gas pressure is 1.5MPa,the maximum cooling range is 2.46℃.2)The Young’s modulus of coal affects the temperature change of coal.The larger the young’s modulus of coal is,the more obvious the reaction effect is in the process of temperature drop of gas-containing coal body in the process of uniaxial compression,and the time of temperature curve’s turning point of gas-containing coal with initial gas pressure between 0.2MPa and 0.5MPa will be advanced.3)With the decrease of porosity,the temperature of coal body changes little in the process of uniaxial compression,but the time of temperature curve bifurcation is about 2minutes in the early stage of compression.4)By comparing the influence of different factors on the temperature change,the relationship between the degree of temperature change in the uniaxial compression simulation of gas-containing coal is obtained as follows: the initial gas pressure of coal > the young’s modulus of coal > the initial porosity of coal.