整条公路隧道通风与净化的三维数值模拟

3D Numerical Simulation of Ventilation and Purification of Whole Highway Tunnel

现有的理论分析方法难以分析风速、污染物分布不均对隧道空气净化的影响,难以发现净化通风系统可能出现的问题。为准确地预测带有净化站的整条公路隧道内污染物的分布情况,建立考虑射流风机、车辆运动及净化站等因素的相互耦合作用的数值模型,对不同通风、净化和交通情况下隧道内的空气流动和污染物分布进行预测,并对模型进行验证。利用该模型对一采用旁通型净化站的实际公路隧道内的空气流动和污染物分布进行数值模拟。结果表明:1)隧道内空气流动不是一维的,在旁通净化站处的主隧道中存在空气回流现象;2)净化站的存在导致了局部通风量的下降,使净化段的主隧道污染物质量浓度突然升高,达到整条隧道的最大值;3)在设计此类净化通风系统时,应该校核"与旁通风道平行的局部主隧道段末尾处"的污染物水平不高于相应的限值标准。

The influence of nonuniform distribution of air velocity and contaminant concentration on purifying effect in highway tunnel can not be analyzed by the existing theories. In order to accurately predict the pollutant distribution in the whole tunnel with purification station,a three-dimensional numerical model which includes the coupled effects of jet fans,moving cars and purification station is established and validated. The model can predict the air flow and pollutant distribution under different ventilation,purification and traffic conditions; and it is used to simulate an actual urban tunnel with bypass-type purification station. The results show that the air flow in the tunnel is not one-dimensional,and air circulationis found in the main tunnel between the inlet and outlet of the purification station; the purification station can decrease the air flowrate in the main tunnel adjacent to the purification station,which results in the maximum concentration of pollutants in the main tunnel close to the outlet of the purification station. It is therefore suggested that this re-circulation phenomenon should be taken into consideration and the pollutant concentration in the main tunnel close to the outlet of the purification station should be taken as the check point when designing such kind of ventilation and purification system of highway tunnel.