地铁隧道排烟口无量纲结构参数与局部阻力研究*

针对现有行业规范中的排烟口结构参数尚不明确的问题，依托过海瓦贵区间隧道，搭建隧道通风排烟模型实验系统。设定11种排烟口面积工况，结合实验与数值模拟，得到排烟口上、下游的静压值和风速。引入动能修正系数，推导出基于上下游能量差的排烟口局部阻力表达式，绘制出无量纲面积比与局部阻力系数曲线族。研究结果表明:排烟口长宽比值较大时，不利于排烟口下方风流流动；在同一风机组合工况下，当排烟口面积缩小时，局部阻力系数会呈现出先减后增的趋势；提出排烟口最优结构长宽比为1.06。研究结果可为相关规范制定提供参考，并为防灾救灾提供理论支持。

Study on dimensionless structural parameters and local resistance of smoke vent in metro tunnel

In view of the unclear structural parameters of smoke vent in the existing industry specifications,a model experimental system of tunnel ventilation and smoke exhaust was built relying on the sub-sea Wagui running tunnel.11 sets of operating conditions of the exhaust vent area were set,and the static pressure and wind velocity at the upstream and downstream of exhaust vent were obtained combining with experiments and numerical simulation.The kinetic energy correction coefficient was introduced,then the expression for local resistance of the smoke vent based on the energy difference between upstream and downstream was deduced,and the curve family of the dimensionless area ratio and the local resistance coefficient was drawn.The results showed that when the length-width ratio of the exhaust vent was large,it was not conducive to the airflow flowing under the smoke vent.Under the same combined conditions of fan,when the area of smoke vent was reduced,the local resistance coefficient presented a trend of decreasing first and then increasing.The optimal structural length-width ratio of smoke vent was 1.06.The results can provide reference for the formulation of relative specifications and theoretical support for the disaster prevention and rescue.