| At present,Gaoligong Mountain Tunnel is faced with serious heat damage problem.The non-manual cooling of the tunnel can no longer meet the requirement of working face cooling,so it is necessary to adopt artificial cooling measures.At present,the manual cooling and cooling system of tunnel is lack of special design data,so the system design can only be carried out by reference to the design code and manual of central air conditioning system.In view of the obvious difference between tunnel cooling engineering and building air conditioning,whether the design method,system form or system operation parameters should be different,otherwise,the tunnel artificial cooling system will be complicated,large investment and high operating cost.Therefore,it is of great practical significance to study the system simulation and operation parameter optimization of the tunnel artificial cooling system.Firstly,the heat source of the tunnel is analyzed and calculated,and the cooling amount needed in the excavation face is obtained.According to the actual situation of the tunnel,the optimal artificial cooling and cooling mode of the tunnel is determined,and the main equipment of the system is selected.According to the conservation law of fluid flow,the hydrodynamic model is established,and the thermal environment of tunneling face is simulated by FLUENT software.The velocity field and temperature field distribution of wind flow in excavation roadway are obtained,and the optimum cooling area is obtained.That is to say,the temperature can be lowered below 28℃at30m away from the working face,which can meet the requirement of cooling the working face.Secondly,the mathematical model of the energy consumption components of the tunnel artificial cooling system is established,the main variables affecting the energy consumption of the system are analyzed,and the mathematical model is fitted and verified accurately.The energy consumption simulation platform of each energy dissipation component is established by using Matlab/Simulink simulation software,and the operation characteristics of each energy dissipation unit are analyzed by simulation calculation.According to the relation between input and output,the simulation platform of cooling water system and chilled water system is set up,and theenergy consumption characteristics of the system are analyzed.Finally,an objective function with the lowest annual conversion cost of the tunnel artificial refrigeration cooling system is established,and the objective function is optimized by genetic algorithm.The results show that when the temperature difference of the cooling water in and out of the cooling water is 5.62℃and the difference of the return water temperature of the frozen water is 10.4℃,the annual conversion cost of the artificial cooling system of tunnel is the lowest,and the outlet temperature of cooling water is 30.3℃and the outlet temperature of frozen water is 5.3℃.At the same time,the optimized diameter of cooling water pipe and frozen water pipe are obtained by optimization calculation.The optimization results show that the annual conversion cost of the tunnel artificial cooling system after optimization is lower than that before the optimization. |
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