| The body of integrated pipe gallery lies underground,which belongs to an enclosed structure.Due to the poor air circulation inside the power cabin,a large amount of heat dissipation emitted from the cable under the airless condition will lead to a rapid increase of temperature inside the cabin,and the accumulation of high temperature air in some areas will occur,which is not conducive to the inspection and maintenance for the maintenance people.Under the background that the theoretical research of the construction of integrated pipe gallery in our country,especially the research on the existing mode of power cabin ventilation system is not quite perfect,it is necessary to conduct research on ventilation convection heat transfer in power cabins that contain a large amount of cables and have too much heat emission in order to eliminate the gathering area of high temperature air and exclude the heat emission of cable in time,ensuring the safety and efficiency of power cabin,providing maintenance people with good maintenance environment.This thesis took the power cabin of an underground integrated pipe gallery in Shenyang City as research objective,surveyed people engaged in civil related industries to understand various problems faced during the design of ventilation system of underground integrated pipe gallery,summarized relevant impact factors related to the effect of ventilation heat dissipation in the power cabin of pipe gallery in Shenyang.Based on the study of structure characteristics of the power cabin of pipe gallery,and determined the typical operating conditions in numerical simulation combined through combining with local climatic conditions in Shenyang.Gambit was used to establish geometric model of power cabin,and Fluent simulation software was used to study ventilation and heat dissipation problem of power cabin.Firstly,based on questionnaire survey,numerical simulation was carried out under natural ventilation condition for two typical seasons,winter and summer.Simulation results show that under natural ventilation condition,high temperature air accumulated in middle post segment of power cabin continuously,and the accumulation interval in summer is longer than that in winter.The effect of ventilation and heat dissipation is very poor in cabin,which is unable to satisfy the requirement that temperature in cabin could not be higher than 40℃ in.Therefore,mechanical ventilation system should be introduced to eliminate high temperature air accumulation areas.Secondly,under the mechanical ventilation(natural intaking and mechanical exhausting)conditions,numerical simulation was conducted respectively for summer with the ventilation rate 2-5times/h,and winter with the ventilation rate 2-4times/h.By comparing and analyzing,and considering the energy-saving requirements of real engineering equipment,the highest temperature of the power cabin of pipe gallery was finally determined within within the range of 37.85-38.85℃,the maximum wind speed in the central region of the cabin is 1.32m/s,which meets the requirements that the optimal rate of air changing is 4 times/h in summer.The highest temperature of 37.85℃ in the power cabin,and the maximum wind speed in the central region 1.24m/s meets the requirements that the optimal rate of air changing is 3times/h in winter.But the inlet air temperature in winter is extremely low,the entrance part of the cabin cannot meet the requirement of temperature could not lower than 5℃ in the tunnel of controlling cable.Therefore,by modifying the angle of the air inlet shutter blade(with respect to the vertical direction),the blade Angle was finally determined to be 45°～60°,the temperature within the power cabin in winter to meet the requirements of higher than 5℃.Thirdly,numerical simulation was carried out on ventilation interval length of 200m,180m and 160m respectively under natural ventilation condition.It could be conclude that reducing ventilation interval length would greatly shorten the length of high temperature air gathering area in power cabin.When ventilation interval length was reduced to 160m,mechanical ventilation system should also be introduced in summer,but there is no high temperature air gathering area in winter and the temperature in the end zone was only 38.85℃.It proved that the power cabin with 160m ventilation interval length can exclude heat emission from cable only by natural ventilation and,and this meet the requirements.Finally,hope the results of this research can provide some reference for the design of ventilation system of the power cabin of underground integrated pipe gallery in Shenyang,and for subsequent ventilation system construction projects. |
PDF Full Text Request