| With the development of economy,mineral resources are continuously exploited and utilized.At present,shallow mineral resources in China are gradually being mined,and deep mining has become the main trend of future mining.However,as the depth of mining increases,the thermal environment in the deep mine gradually deteriorates due to the self-compression heat of the air and the rising temperature of the surrounding rock,which not only seriously restricts the safe production of the mine,but also threatens the health of the miners.Ventilation and cooling are the main way to control heat damage in deep wells.However,due to the complex environment of stope working face and roadway,ventilation conditions directly affect the energy consumption of refrigeration and ventilation systems and the efficiency of ventilation.Therefore,it is of great theoretical and engineering significance to carry out numerical simulation and experimental research on the air distribution in the single-head stope and return air shaft,and form a complete ventilation and heat management scheme for reducing the energy consumption of the refrigeration system and improving the economy of metal mines.In this paper,based on the survey data of deep metal mines,an experimental platform for the stope ventilation conditions is built,and an experimental study is carried out on 15 air distribution modes in the stope.The ventilation effect in the Z direction is the best.Combined with the experimental platform,a numerical model of ventilation and cooling in the stope was established,and the experimental results of ventilation and cooling under different working conditions were compared with the numerical simulation results.The error was less than 5%,which verified the validity of the model.The velocity field and temperature field in the stope under different air distribution are obtained through the simulation model,PMV(Predicted Mean Vote)is selected as the thermal comfort evaluation index,and the velocity field and temperature field in the stope under different air distribution conditions are summarized.The cooling effect of 15 air distribution methods and their respective applicable stope working conditions were analyzed.Then,the PMV cloud images under 15 air distribution modes were calculated.Through the multi-condition numerical simulation of variable inlet air temperature and variable wind speed,the temperature field and velocity field distribution cloud map in the stope under different wind speeds and inlet air temperatures are obtained.The change law of the velocity field,the influence of wind temperature and wind speed on the ventilation and cooling effect is evaluated by introducing the heat dissipation load in the stope.The temperature is more conducive to the ventilation and cooling of the stope and the reduction of system consumption.Aiming at the air distribution of the air-cooling tower heat exchanger in the roadway,a numerical model of the fin-tube heat exchanger was established combined with the porous media model.The tower layout is simulated.The results show that in the case of no fan,with the increase of the distance between the air cooling towers,the heat exchange efficiency of the air cooling towers in the return air shaft increases.In the case of the same spacing,the heat exchange effect of staggered arrangement of aircooling towers is better than that of parallel arrangement of air-cooling towers.According to the comparison of simulation results with and without fans,it shows that the problem of low heat exchange efficiency of air-cooling towers caused by the series connection of air-cooling towers can be solved by adding fans.According to the comparison of the simulation results with and without baffles,it is proved that adding baffles can improve the heat exchange efficiency of the air-cooling tower in the return air shaft in the parallel arrangement. |
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