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The hot and humid environment in the coal mines negatively affects miners' health and mental health. This paper analyzes the factors that affect the human body heat dissipation, puts forward the concept of dressing rate, and uses the dressing rate to correct the human skin heat dissipation loss and sweat evaporation heat dissipation loss in the underground environment. A human-body thermal comfort model suitable for the hot and humid mine environment is constructed. Then the evaluation index UPMV of thermal comfort in hot and humid mines is proposed, and the mathematical model of human thermal comfort evaluation is constructed which improves the accuracy of human thermal comfort evaluation in hot and humid mines. Lastly, a software system of thermal comfort evaluation for hot and humid mines is developed, which is used to evaluate the thermal comfort of the human body at different working points of horizontal mining roadway in Shoushan mine, and the accuracy of the evaluation model is validated. The research results provide a theoretical basis for the evaluation system of human thermal comfort in hot and humid environments, and provide a reference for a scientific and reasonable arrangement of underground production.

With the depletion of shallow metal mineral resources, deep mining has become more common. In the process of deep mining, heat hazards in mines seriously threaten the health of personnel and the safety of mining operations. According to the flow and low-temperature characteristics of abundant water in Maoping Lead Zinc Mine, this paper proposes the direct use of the low-temperature water inflow of the mine as the cold source by which to conduct the heat exchange with a single spiral-tube heat exchanger for mine cooling. An experimental platform was built for the cooling system to allow us to explore the mechanism of the influence of the inlet air volume and air temperature and the inlet water temperature and flow on the cooling effect of the single spiral-tube heat exchanger. It was found that with the increase in the inlet air volume and inlet water temperature, the cooling efficiency of the heat exchanger decreased, while with the increase in the inlet air temperature, the cooling efficiency of the heat exchanger increased. Within the experimental range, 127.2 m3/h was found to be the optimum inlet air volume, and 33.0 °C was the most appropriate inlet air temperature; the water temperature of Maoping Coal Mine is about 20 °C throughout the year, and the industrial test site can reduce the wind temperature of 31.5 °C to 23.9 °C. The inlet water flow is positively related to the cooling effect. With the increase in the water flow, the outlet temperature of the air flow at each working point was continuously reduced, and the cooling effect of the heat exchanger was improved. The moisture content of the inlet air flow can be reduced by increasing the low-temperature inlet water flow. Through experiments, the feasibility of the cooling system that directly uses the mine’s low-temperature water as the cold source was verified. A multiple linear regression analysis equation for the cooling system model is proposed, which provides a reference for formulating effective measures to prevent and control heat hazards in mines.

Abstract: The flame propagation velocity and the flame temperature was Proposed to represent the flame intensity. The influence of open/closed-end conduit on flame intensity in different work conditions were studied, such as lubricate, sticking heat-insulated materials in ignite side, etc. The experimental conduit is rectangular in cross section, measuring 80mm×80mm in width. The research result shows that when the gas explosion, the influence of open/closed-end conduit on flame intensity in gas explosion initial stage is relatively little. After that, the flame acceleration degree, the acceleration range, the flame propagation velocity maximum, in open-end conduit is greater than that in closed-end conduit, but the flame temperature at the back part in open-end conduit is obviously less than that in closed-end conduit. The reason is that the reflected waves suppress the flame propagation, and produce the oscillation burning, increase the burning rate. [Copyright &y& Elsevier]