顶部多开口隧道热压通风模拟研究

Simulation of Buoyancy-driven Natural Ventilation in Tunnel with Multiple Top Openings

顶部多开口隧道能避免汽车尾气在隧道峒口集中排放,且利用自然通风降低隧道运行成本。而实际运用中自然通风作用能否达到隧道的需风量要求是不可知的。本文通过对称的隧道模型采用数值模拟的方法研究顶部多开口隧道阻滞工况自然通风规律。通过研究得到:可以用简化的尾气混合温度模型研究隧道热压通风;奇数对称顶部开口隧道有利于热压通风;对称分布的顶部开口数量超过3个时,隧道顶部开口通风量呈"中间小,两边大"的分布。

Top openings in tunnel can be used to promote natural ventilation and to avoid exhausting only at the exit of the tunnels.However,the outcome of adding top openings to the tunnel could be unpredictable in practices.This paper applied the numerical method to simulate the effect of natural ventilation in tunnel with top openings under traffic block conditions by adopting a symmetrical tunnel model.The results shown that: 1) the simplified exhaust gas mixing temperature model can be used to study on the buoyancy-driven natural ventilation in tunnel; 2)tunnel with odd uniform top openings is advantageous to the natural ventilation;3)when tunnel has more than three uniform top openings,the ventilation rate increases from middle opening to the sides openings.