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A STEADY CALCULATION MODEL ON HEAT AND HUMIDITY PARAMETERS OF AIRFLOW IN HEAT HAZARD MINES

In order to solve the problem of heat hazard in the main roadway of a shaft bottom, this paper establishes a steady calculation model to predict air conditioning airflow in the shaft. Based on the steady heat transfer theory, the model was used to calculate the convective heat and mass transfer between the airflow and shaft wall, as well as the heat conduction between the shaft wall and heat adjusting circle of wall rock. According to the analogous principles of heat and mass transfer, the water vapor transfer between the airflow and shaft wall was calculated. Furthermore, the energy balance equation was set up to consider the heat and humidity exchanges between the airflow, shaft wall, heat adjusting circle of wall rock, and gravity compression heat of the airflow. Meanwhile, the difference model was derived to calculate the heat and humidity parameters of the vertical shaft airflow. The developed model was applied to the auxiliary shaft at the Wutongzhuang Coal Mine. The calculated values of the heat and humidity parameters of airflow in the model were compared with the measured values in the shaft bottom. The results showed that the calculation errors of dry bulb temperature and relative humidity were less than 5.4% and 6.1%, respectively. Hence, this model is proper and acceptable, which could be used to predict the heat and humidity parameters of air conditioning airflow in a coal mine. The study is significant to the pithead cooling system design.