Research On Numerical Simulation And Control Technology Of Thermal Environment In Deep Roadway Of Metal Mine

With the increase of mining depth,thermal pollution has become a major new problem restricting efficient mining and green mine construction.Taking the levels of-960 m and-1140 m in Xishan mining area of Sanshandao Gold Mine with typical characteristics of deep well heat damage as an example,this paper studies the change of wind temperature,the heat release of main heat sources and the application of ventilation and cooling technology in the target area.The main research contents and achievements include :(1)The data of average ground temperature gradient,temperature and humidity along the wind flow,wind speed and power of mechanical and electrical equipment in the deep part of the mining area are obtained through field detection,which lays the foundation for wind temperature prediction,heat release calculation of main heat sources and numerical simulation of thermal environment,and serves as the basis for reliability verification.(2)Inductive derivation of the heat exchange mathematical model of the airflow through the roadway and independently developed a software for predicting the air temperature of the roadway.When the software is applied to the site,the local heat source with the highest heat contribution rate at-960 m level is the heat release of mechanical and electrical equipment,and the local heat source with the highest heat contribution rate at-1140 m level is the heat release of hot water,with the heat release rates of 230.73 k W and 530.62 k W,respectively.The main causes of thermal pollution are clarified to provide guidance for non-mechanical cooling work.From the intake patio to the return air patio,the air temperature continues to rise,and the temperature of the excavation face is the highest.It is a key task to determine the thermal environment control of the excavation face.Comparing the predicted results with the measured temperature,the error is basically within 1 °C,and the maximum deviation occurs at a tunneling face at a level of-960 m.The deviation value is 1.02 °C,and the software is reliable.(3)Numerical simulation is carried out on the basis of field test data and key heat sources and key areas proposed by wind temperature prediction software.The thermal environment without mechanical cooling measures was simulated.The results show that the formation of airflow path is crucial to the improvement of wind speed in the working area without mechanical ventilation.The average temperature of-960 m level excavation face is 31.337 °C,and the average temperature of-1140 m level excavation face is 32.296 °C.Comparing the simulated temperature with the measured temperature,the maximum deviation is 1.307 °C,and the simulation has practical guiding significance.The simulation results of PE and PF local ventilation cooling system are compared and analyzed from the aspects of cooling effect,flow field distribution and air pressure inside the air duct.The PE system can significantly improve the airflow speed of the exploration roadway and directly extract the heat released by the heat source,but the cooling effect is limited and the material requirement of the air duct is high.The PF system has a large effective range and a small power required by the fan,which can significantly improve the temperature of the tunneling face according to the demand.The PF system is more in line with the on-site cooling demand.Nine groups of different inlet airflow temperature and velocity conditions were set at the two levels,and the PF system simulation was carried out to study the change of airflow temperature and velocity in prospecting roadway and heading face,and to determine the local cooling scheme that meets the requirements of " Metal and Non-metal Mine Safety Regulations " and human thermal comfort.(4)The economic comparison and selection of numerical simulation cooling schemes were carried out by using the " Technical Specification for Mine Cooling " discount cost method,and the final local cooling scheme was determined and tested in the mine site.After trial operation,the temperature of heading face at the same position decreased from 33.5 °C to 24.7 °C,and the cooling effect was remarkable.