隧道宽度对侧向排烟系统排烟效果的影响研究

Study on the influence of tunnel width on the smoke exhaust effect of the lateral smoke exhaust system

为了研究不同隧道宽度对侧向排烟系统排烟效果的影响,基于FDS数值模拟分析方法,结合不同隧道宽度和排烟量对隧道拱顶温度、烟气层厚度及排烟效率等参数进行分析。结果表明:在相同边界条件下,隧道越宽,拱顶纵向温度衰减越剧烈,纵向方向烟气蔓延长度越长;在不同隧道宽度下,排烟量越大,侧向排烟效率越高;排烟效率受隧道宽度的影响较大,在相同排烟量下,随隧道宽度增加,各排烟阀排烟效率及总排烟效率均呈递减趋势,隧道宽度从10 m增至20 m,排烟效率降低了18个百分点左右;在隧道宽度为20 m时,不同排烟量下排烟效率均在50%左右,表明隧道宽度在20 m以上时排烟效果相对较差,建议隧道宽度大于20 m时不宜采用侧向排烟方案。

This paper intends to take the horizontal tunnel under the lateral smoke exhaust system as the research object,and sets up different tunnel widths(10 m,13 m,15 m,18 m and 20 m)and smoke exhaust volume(220 m~3/s,240 m~3/s and 260 m~3/s),so as to explore and find out its influence of different tunnel widths on the smoke control from the smoke exhaust effect.In this paper,based on the FDS numerical simulation analysis method,combined with different tunnel widths and smoke exhaust volume,the tunnel vault temperature,smoke layer thickness and smoke exhaust efficiency are analyzed to obtain the applicable tunnel width range in the lateral smoke exhaust mode.The results show that under the same boundary conditions,the wider the tunnel is,the more severe the longitudinal temperature attenuation of the vault,and the longer the length of smoke spread in the longitudinal direction are.However,the maximum temperature of the vault is not greatly affected by the width of the tunnel,which is around 600℃.Under the same tunnel width,with the increase of smoke exhaust volume,the smoke extraction efficiency of the smoke exhaust valve increases significantly,and the length of the smoke spread in the longitudinal direction decreases.The smoke exhaust efficiency is greatly affected by the width of the tunnel.Under the same smoke exhaust volume,with increasing the width of the tunnel,the exhaust efficiency of each exhaust valve and the total exhaust valve shows a decreasing trend.The tunnel width varies from 10 m to 20 m.The smoke efficiency is reduced by about 18%,and the length of the smoke spread in the longitudinal direction is increased.Therefore,in the lateral smoke exhaust mode with a tunnel width of 10-20 m,the width of the tunnel becomes narrower,which is more conducive to the control of the smoke.When the tunnel width is 20 m,the exhaust efficiency is close to 50%under different smoke exhaust volumes.It shows that when the tunnel width is more than 20 m,the smoke exhaust effect is relatively poor.So,it is recommended that the lateral smoke exhaust scheme should not be adopted when the tunnel width is greater than 20 m.