Study On Thermal Comfort Of Mine Workers In Underground Environment

The high-humidity working environment prevents miners from operating for a long time and with high intensity,making the equipment difficult to dissipate heat,reducing production efficiency and attendance rates,and easily causing safety accidents such as thermal injury or mine fire.Therefore,accurately evaluating comfort of miners is also an issue we should consider.Based on the thermal comfort evaluation and thermal balance equations,the heart rate,blood pressure,external auditory canal temperature,thermal sensation,and draught sensation were analyzed.This study is mainly divided into two parts: The first part is to select several indexes from the existing thermal comfort evaluation indexes to theoretically calculate and analyze thermal comfort and thermal sensation under different experimental conditions,and find out different.The second part is to measure and analyze the heart rate,blood pressure,external auditory canal temperature,draught sensation and thermal sensation under different experimental conditions by simulating underground environment of mine,and explore changes.Theoretical calculated values and measured values of thermal sensation were compared and analyzed.The measured values were subjected to non-linear regression,and the regression relation was obtained.The experimental study in this paper is divided into two stages,a total of 44 experimental conditions,220 experiments,21 fingers whose thermal resistance are 0.90 clo,participated in the experiment.The first stage explores the changes in human physiological parameters,draught sensation and thermal sensation at different environmental temperatures,relative humidity,and metabolic rate.The second stage explores the same changes at different wind speeds.The results show that the thermal comfort of human body is simultaneously affected by the four factors of ambient temperature,relative humidity,wind speed,and labor intensity.In high-humidity environment,the environmental temperature and metabolism rate have the greatest impact on thermal comfort,while the relative humidity has a smaller effect;under the same labor intensity,the temperature effect increases with the increase of temperature;the improvement effect of increasing wind speed on the human thermal sensation varies with the increase in environmental temperature and metabolic rate,and the increase in environmental temperature at 30? and above has basically no improvement in wind speed.Real-life experiments show that only 22?24?,80%,2.5m/s,moderate labor(2.2met)conditions are "thermal comfort" conditions,and other conditions deviate from the comfort zone.Under severe working conditions,most of the test subjects were in a "hot" and above heat sensation and sweated a lot.When the ambient temperature is less than 24 ?,labor intensity effect> temperature effect> superimposed effect> humidity effect;at 26 ?,temperature effect = labor intensity effect;at 28 ??34 ?,temperature effect> labor intensity effect> superimposed effect(The effect of improving thermal comfort)> humidity effect;when the ambient temperature is 36?,temperature effect> superimposed effect(improving thermal comfort effect)> labor intensity effect> humidity effect.It can be obtained through theoretical analysis and experimental study that temperature and metabolic rate are the factors that most affect human thermal comfort.When metabolic rate is constant,reducing ambient temperature is an effective means to improve human thermal comfort.The effect of increasing wind speed on thermal comfort of human body decreases with the increase of ambient temperature and metabolic rate;thermal sensation is closely related to ambient temperature,and the relationship between thermal sensationambient temperature,thermal sensation-ambient temperature-humidity-wind speed-moderate labor are obtained respectively.It is suggested that wind speed should be controlled at 1m/s?2.5m/s when designing parameters of mine.