Heat Transfer Characteristic Research Of Wall Rock And Airflow On High-temperature Mine

With the large-scale development of coal resources in our country,high-grade mineral resources buried in the shallow seam are being gradually exhausted. With the increase of mining depth, mine heat hazard has become the sixth coal mine disaster following water, fire, gas, dust and roof, so it is urgent to control the heat hazard in deep mine. The heat dissipation of roadway surrounding rock is the main source of heat in the mine, so research the heat transfer characteristics of surrounding rock of roadway and wind is the basis of ventilated cooling measures.This article using the similarity theory to establish 1:10 humid of roadway convective heat transfer experimental model, Selection of surrounding rock temperature of 36 ?, 38 ? and 40 ? respectively, Supply air temperature of 18 ?, 20 ?, 22 ?,24 ?, 26 ?, 28 ? and 30 ? respectively, Inlet wind speed of 1 m/s, 1.5 m/s, 2 m/s and 2.5 m/s, a total of 84 groups of experiment. Within the test bench roadway, we will research the heat transfer characteristics of surrounding rock and air flow under different working conditions. The temperature field of heat transfer of the surrounding rock and air flow in the mine roadway with the corresponding working conditions is obtained, and analyzes the influence law of the air supply parameters on the temperature field of the roadway. The results show that under the condition of given wall temperature, the wind speed is greater, the temperature difference between the inlet and outlet of the roadway is smaller, and the temperature rise is small. Under the condition of given wall temperature and wind speed, the lower the temperature, the greater the amount of heat energy absorbed by the surrounding rock. The temperature difference between the airflow and the wall rock in the roadway decreases with the increase of the length of the roadway, so the change of the wind temperature gradually tends to be gentle.According to the experimental results further analysis, we obtained the effects of wall temperature, air temperature and air velocity on the coefficient of convective heat transfer in different conditions. When the supply air velocity and the supply air temperature increase, the convective heat transfer coefficient all rises, but as the wall temperature rises, coefficient of convective heat decreased. But the influence of the supply air velocity to the convective heat transfer coefficient much larger than the influence of the supply air and surrounding rock temperature. So as a variable with the supply air velocity, combining the difference value between the temperature of surrounding rock and air in the roadway, applying the SPSS, concluding the regression equation of coefficient of convective heat transfer is:h=?0.055?t²-2.171?t-26.785?e^0.4V. Finally, we obtain the relationship of criterion of heat transfer between Nusselt number and Reynolds number:Nu=0.0045Re^0.809. And provide the basis for roadway and surrounding rock heat transfer calculation with high temperature and humidity.