特长隧道群污染物窜流规律及新型通风方式研究

Study on the Rule of Pollutant Dispersion and New Ventilation Mode in Super-long Tunnels

特长隧道群洞口多位于峡谷中,上游隧道污染物易扩散至下游隧道造成二次污染并大大增加下游隧道的通风负荷。为掌握特长隧道群毗邻隧道的污染物窜流问题及影响,以浙江省景文高速公路工程叶麻尖特长隧道群为依托,建立流体力学分析模型,以CO为示踪污染物,分析隧道洞内外温差、峡谷风速和进出口风速比等因素对窜流比的影响。分析表明:隧道出口污染气流与环境温差越大,或者峡谷风风速越大,或者隧道进出口风速比越小,则窜流比越低;不利工况下,叶麻尖隧道左、右线隧道的窜流比分别约为58.8%和55.9%。最后,针对叶麻尖特长隧道群提出了竖井送排风+互补风道分流+射流风机的新型绿色节能通风方案。

The entrances of super-long tunnels are located in canyons,and the pollutants in the upstream tunnels are easy to disperse to the downstream tunnels,causing secondary pollution and greatly increasing of the ventilation load of the downstream tunnels.In order to understand the problem and influence of pollutant dispersion in adjacent tunnels of super-long tunnels,taking Yemajian super long tunnel group of Jingwen expressway project in Zhejiang province as an example,a CFD analysis model is established.The influences of temperature difference inside and outside the tunnel,wind speed of canyon and wind speed ratio of inlet and outlet on the dispersion ratio are analyzed with CO as a pollutant tracer.The results show that the larger the temperature difference between the air flow at the exit of the tunnel and the environment,the greater the wind speed in the canyon,or the smaller the wind speed ratio at the entrance and exit of the tunnel,the lower the dispersion ratio;in unfavorable conditions,the dispersion ratios of the left and right Yemajian tunnels are about 58.8%and 55.9%respectively.Finally,a new energy-saving ventilation scheme is proposed for the Yemajian super-long tunnels,with a combination of shaft ventilation,complementary air duct diversion,and jet fan ventilation.