特长公路隧道洞口污染物扩散的有限元法模拟

建立了公路隧道洞口处排放污染物输送与扩散所遵循的方程组。针对秦岭终南山特长公路隧道洞口环境特点对方程组进行了简化。采用有限元法,考虑洞口排放源、洞口边界与东线洞口排放及隧道西线洞口进风的影响,对该特长隧道洞口排放形成的垂直和水平二维CO质量浓度分布及通量场进行了数值计算。结果表明:以隧道排口为中心形成了随距离明显递减的CO质量浓度场;隧道西线洞口排放CO对东线洞口的进风空气质量产生明显影响;进一步数值分析发现,在隧道外两洞口之间增加一墙体可有效减小两洞口之间的污染影响。

Simulation of Pollutant Diffusion near Extra Long Highway Tunnel Portal with Finite Element Method

The sets of equations,which could be used to calculate pollutant convection and diffusion near highway tunnel portals,were developed.System of equations was simplified based on taking into account portal surroundings and ventilation outlets for Qinling Zhongnanshan extra long highway tunnel with twin bores.The CO concentration distribution and flux field for both horizontal section and vertical section around outside portals were numerically calculated using finite element method.The results show that firstly CO concentration around exit of exhaust air of bore is relatively high and has quick decrease with increasing distance away emitting portal;secondly,since two bores of the tunnel lie immediately side-by-side,CO emitted from one portal(west) by longitudinal ventilation system has an obvious pollution effect on air which flows into the other portal(east);thirdly by setting a wall between the portals,which exhaust air is sucked in,pollution impact can be greatly reduced.