Study On The Heat Transfer And Heat Harm Control Of Driving Face In Deep Mine

In the world energy consumption structure, fossil energy still remains the dominantposition. With the growth of energy demand and mining depth, the number of mineswith heat hazard is increasing. It has severely constrained the development of coalmines. Currently, mine heat hazard has become the sixth coal mine disaster followingroof, gas, fire, dust and water. Therefore, further study of heat hazard has become atechnical focal point of the development of coal mining. The high temperature andhumid environment not only harm workers’ health irreversibly, but also reduce laborproductivity. The thesis takes the driving face which is one of the hottest work place asthe study object. According to the study of heat transfer characteristics and mine heatharm control, we can get the heat transfer relationship of driving face. Furthermore,systematic study is done about the law of heat harm in deep mine on the climate,geothermal and heat resources and the calculation formula of cooling load is deduced.Then it puts forward the system design for the specific coal mine and develops theworld’s first semi-closed mine cooling system. Data analysis shows that the coolingeffect is good and meets the design requirements.The thesis’s main research contentsand conclusions are as follows:（1）Study on heat transfer in driving face.According to the ventilation and heat transfer characteristics of driving face in hotmine, and on the basis of theoretical analysis of general parameters in engineeringpractice, the heat transfer characteristics are investigated by ANSYS numericalsimulation and the ratio of1:3similar experiment, the number of numerical simulationand experimental study are respectively840and280group. Through the comparison,simulation and experiment results have high degree of coincidence both on range ofvalue and variation tendency. Then the concrete forms of heat transfer coefficientcorrelation are made through regression analysis of numerical simulation results andexperimental results. Similarly, in order to combine with practical application, thisthesis sees the driving face head-on, wall rock and airflow as a whole, conductsnumerical simulation on840combinations respectively, does regression analysis of theexperimental data and gets the correlation of heat transfer coefficient.（2）Research on the law of heat harm in deep and hot mineBased on the law of heat harm in deep and hot mine, the change curve of temperature, relative humidity and air pressure between the ground and underground isvery similar and synchronous. Generally, the climate parameters on the ground haveremarkable effect on climate parameters under the mine. For the distant areas ofdeep-high temperature mine, because of special conditions of development, long airwayand other reasons, the climate on the ground has a little impact on the coal mine. Theheat damage is mainly caused by high temperature of the geothermal.Geothermal downhole drilling test theory and calculation method of thickness ofheat-adjusting layer are deduced. With the increase of the depth of coal bed, the originalrock temperature is still increasing. As the role of geological faults, the geothermaltemperature has significantly increased dramatically in the process. The thesis hasstudied and confirmed the type of geothermal, temperature and depth of constanttemperature zone. Through quantitative analysis in the heat dissipating of various heatsources along airway, the proportion of heat dissipating of various heat sources isobtained.（3）Research on heat-harm controlThrough the deep study of heat-harm control in high temperature driving face, thecalculation formula of refrigerating capacity is deduced. The heat dissipating capacity ofheat source in driving face is calculated, and the cooling system has been designed andinstalled. The practice shows that the system is stable and reliable, and also has goodcooling effect and meets the design requirements absolutely. Through the PLC tocontrol the system, it can realize many kinds of protection function. Within the100mfrom the heading face, the temperature reduction range of dry bulb mean temperatureaverage is5.6℃, and the maximum is7.5℃.The wet bulb mean temperature is8.5℃,and the maximum is11℃, and the fall scope of the relative humidity is20%on average.YongChuan coal mine local refrigeration cooling system is successful, which verifiesthe rationality of the experiment and the theory in this paper. The refrigeration coolingsystem can be used as a demonstration of mine heat harm control, and it is worthy ofbeing used widely.