Prediction And Control Model Of Thermal Comfort In High-humidity Mine

High-humidity underground working environment is one of the main reasons for mining safety production accidents.The research on the prediction of thermal comfort of miners can realize the control of thermal comfort in the high-humidity mines,which can not only arrange reasonable working hours for miners,but also reduce the threat of the thermal environment to the physical and mental health of miners,ensure production safety.Through the analysis of the factors affecting the thermal comfort of the high-humidity mine and the application scope of the thermal comfort evaluation index,the thermal stress index HSI is selected as the evaluation index of the thermal comfort of the high-humidity mine.Based on the numerical simulation method to predict and calculate parameters such as temperature and humidity in the mine,combined with the thermal balance principle of miners,the thermal comfort prediction model is established.Considering the influence of the surface vapor pressure during the migration and evaporation of water molecules,an evaporation calculation method with modified surface vapor pressure is proposed to calculate the humidity distribution in the mine.And the correctness of the modified surface vapor pressure calculation method is verified.Taking the high-temperature single heading tunnel in a coal mine as the research object,the process of convective heat and mass transfer between the wall and air in the humid and hot environment of the tunnel is analyzed.Based on the principle of thermodynamics,the calculation model of mass and mass transfer in the high-humidity mine is established,and the feasibility of the calculation model of heat and mass transfer is verified.Aiming at the problem of thermal comfort control in the high-humidity mine,the thermal comfort index HSI is selected as the control target,and the control model of HSI about Prandtl number(Pr),Reynolds number(Re)and Grachev number(Gr)is established:HSI=f(Pr),HSI=f(Re),HSI=f(Gr).Finally,the thermal comfort control strategy of the high-humidity mine is formulated based on Pr,Re and Gr.The research on the influence of Pr,Re and Gr on HSI shows that:1)When0.5≤Pr≤0.7,the change trend of HSI value is negatively correlated with Pr.When0.7≤Pr≤0.9,HSI value is positively correlated with Pr.When 0.9≤Pr≤1.2,the HSI value is again negatively correlated with Pr.2)There is a critical value for the influence of Re on the HSI value.When Re is lower than the critical value,HSI and Re are negatively correlated;otherwise,it is positively correlated.The critical values of Re on the miner’s head,waist and ankle are 1.15×10~6,1.05×10~6 and 7.5×10~5,respectively.3)The value of HSI is always negatively correlated with Gr.