| With the development of the social economy, the mining depth is increasing and the heat harm of mine becomes increasingly serious. The main development trend of mine temperature drop technology is mechanical refrigeration for lowering temperation. The choosing of refrigeration equipments need the cooling and humidity load of laneway first. Thus, making the mechanism of heat and humidity exchange between rock wall and airflow in mine clear is the base of mine temperature drop and dehumidification technology. The heat and humidity dissipating from the surrounding rock takes a biggest part of the total load, but the calculation of this part is most difficult. Compared with the calculation of cooling load for air conditioning building, the calculation of cooling load for mine has a higher complexity. Because the heat and humidity dissipating from the surrounding rock is a 3D unsteady process, a number of factors can influence heat transfer coefficient and humidity transfer coefficient, and the mechanism of heat and humidity exchange is quite complicated. At present, empirical formulas of former soviet union is usually used to calculate the cooling and humidity load in Chinese mines. However, some weaknesses exist in these formulas:fist, the parameters needed in these formulas are too many to make the formulas feasible; second, the effect of mass transfer is ignored which makes the calculation result not so precise; third, these formulas of former soviet union can't be applied to calculation for Chinese mines perfectly. In this paper theory analysis and experiment simulation were combined. First, differential equations system of heat and humidity exchange between rock wall and airflow in mine in cylindrical coordinates was derived, and the mathematical modeling was built. Then on the basis of field survey and measurement, the simulation experimental bed system was built under the similarity theory to simulate the process of heat and humidity exchange between rock wall and airflow in mine. The actual sandstone in mine tunnels was replaced with concrete for its similar thermal performance in this experimental bed. The air state parameters at the outlet and temperature distribution in the surrounding rock can be monitored with changing of the temperature, humidity and velocity at the inlet of airflow. By a lot of experimental conditions and statistics methods, the influencing factors and change law of airflow heating and humidifying along the laneway when flowing through wet tunnel walls and surface steady temperature of surrounding rock was concluded, and regressive formulas for heat transfer coefficient and humidity transfer coefficient were obtained. |
