Air-Solid Heat Transfer Theory And Simulation Of Ventilation Cooling In Xiadian Gold Mine

As the mining depth increases,heat damage becomes a common problem in deep well mining.Air-solid heat transfer between the wind and the rock mass is the main cause of heat damage.Relevant literature indicates that ventilation temperature reduction should be preferred when the rock temperature does not exceed 36?.The research is based on the Xiadian gold deposit with typical characteristics of deep well heat damage.The theoretical analysis,field experiment,numerical simulation and similar model are combined to study the application of deep well air-solid heat transfer theory and ventilation cooling technology.Through the test of the multi-level original rock temperature in the Xiadian gold mine,the formula for calculating the temperature gradient of the mine is obtained.After analyzing and calculating the heat generation of each heat source in the mine,it is found that the heat release of surrounding rock and compressed air accounts for nearly 71%.In order to obtain the heat conduction mechanism of the mine heat transfer ring under the multi-factor combination of rock mass properties,roadway physical parameters and ventilation parameters,the long-ventilation mine heat-regulating ring is considered by the steady-state heat conduction model,according to the classical heat transfer theory.The formulas for calculating the temperature and radius of the thermostat are derived.The two formulas are verified by field experiments and numerical simulation experiments,and the errors are within the acceptable range.Considering the seasonal difference of surface climate,the change of air humidity parameters in the well and the influence of surrounding rock heat on the deep thermal environment of the vertical well,based on the macroscopic dynamic heat balance theory,the vertical wind temperature prediction model is established.It is verified by experimental data that the calculation error of the deep airflow temperature in the vertical shaft is within 10?.Based on the analysis and analysis of the simulated wind-air data of the simulated roadway ventilation,the distribution characteristics of the wind-flow temperature field in the roadway are revealed.The wind flow temperature field of the roadway can be divided into the head-blocking zone,the jet-affected zone,the returning wind-stable zone and the externally affected zone.There is a circulating vortex zone in the jet-affected zone,and the lowest temperature of the windflow in the circulating vortex zone.According to the "Safety Regulations for Metallic Non-Metallic M ines",28 ?is set as the target temperature.Through numerical simulation experiments,it is found that when the air volume of Xiadian gold mine is 135.6m3/s,the inlet air temperature should be 21? and below,so as to ensure the air temperature drops at-740m and-780m.After the ventilation design is changed(the air volume is 347.5m3/s),the ventilation can achieve the cooling target for the roadway at the level of-1260m and above.It is difficult to achieve the purpose of cooling only by ventilation below this level.The research results of this subject can provide theoretical basis and technical guidance for the optimization of deep ventilation cooling scheme in Xiadian gold mine.Relevant theories can supplement and improve the theory of deep well ventilation.