Simulation And Optimization Research Of Refrigeration Ventilation System For Deep Metal Mine

With the increment of the depth of metal mines,high temperature heat damage in deep mines has become one of the key constraints mining.Refrigerated ventilation systems for deep metal mines are an important technical tool for heat damage management.However,because of the large stope load,refrigeration and cooling equipment and stope distance,so high energy consumption,high operating costs.Improving mine energy utilization efficiency is the key to realize energy saving and"double carbon" strategy in metal mines.Therefore,in this paper,the global physical modeling analysis is carried out for the refrigeration and ventilation system of deep metal mine,and efficient simulation and optimization research is carried out to control the mine heat damage and improve the performance of the refrigeration and ventilation system.In this thesis,combined with the existing deep metal mine return air system,the deep mine refrigeration and ventilation system is designed,and an experiment platform is built.The experimental results of the experimental system show that when the operating parameters of a primary circuit change,the node parameters and heat transfer of other loops in the system do not change significantly.Only the loop and heat exchanger node parameters or heat transfer have significant changes.The variable frequency pump,pipe network characteristic parameters and heat exchanger conductance are identified by the experimental data.In order to conduct global physical modeling analysis of the system,based on heat flow method and flow resistance network model,heat transfer constraint and flow constraint of deep mine refrigeration and ventilation system were established.Heat transfer model of stope simulation box was established based on convective heat transfer equation.Artificial neural network models of heat exchanger and refrigerator were established respectively based on historical operation data.On this basis,further study the system performance and characteristics,compared with the simulation calculation and experimental measurement of the stope air outlet temperature and heat exchange,the error is less than 7%,and the iteration parameter error is less than 0.5℃.Based on the simulation model,the heat transport rule under varying working conditions is analyzed,which is consistent with the experimental results and verifies the reliability of the simulation model.Combined with the heat transfer and flow constraints of refrigeration ventilation system,the Lagrange multiplier method is used to establish a global optimization model aiming at the lowest power consumption of the variable frequency pump.Combined with the artificial neural network model of the refrigerator and the optimization algorithm of inlet and outlet water temperature design,the iterative algorithm was used to optimize the model,and the optimal operating frequency and the lowest power consumption of the variable frequency pump were obtained.After optimization,the total pump power consumption of the system is reduced by 25.79%,among which the power consumption of the cooling tower loop is reduced by 72.84%.Moreover,when the air inlet temperature of cooler increases,the frequencies and pump power consumption of the corresponding loop,intermediate circulation loop and cooling tower loop increase.When the variable frequency fan frequency of a certain loop changes,the heat transfer of the air cooler and stope simulation box is enhanced,and the systematic pump power consumption increases.Therefore,when the air inlet temperature of air cooler increases,the fan should be operated at a lower frequency to save energy.Additionally,as the air inlet temperature of the cooling tower increases,the frequency and pump power consumption of the intermediate circulation loop and cooling tower loop should increase.Through the simulation and optimization study of this paper,it has important guiding significance for reducing the energy consumption of refrigeration and ventilation system in deep metal mine and realizing the construction of green energy-saving mine.