阻滞下的竖井型隧道自然通风试验与数值模拟

针对竖井型城市公路隧道自然通风的当前研究现状,分析阻滞工况下的流场特征与存在的问题。依据相似准则,搭建局部暗埋段小尺寸模型,设置车辆发热源,测试纯热压作用下的流动速度。采用三维非稳态流动模型,利用FLUENT软件,模拟热压作用下的温度场、速度场,采用试验验证了模拟的准确性。进一步的车速、竖井个数与暗埋段长度的敏感性分析表明:车辆阻滞时,交通风力对隧道内自然通风影响小,热压成为影响隧道流场的主导因素;同一暗埋段内流场不均匀分布,中部远离两端竖井,改变竖井个数对此处流场影响较弱;暗埋段各典型位置风速随暗埋段长度增加而增加。

Experiment and Numerical Simulation on Natural Ventilation for a Traffic Tunnel with Shafts under Traffic Jam

Based on the current research on the natural-ventilated urban transportation tunnel with shafts, the characteristics and problems of flow field under traffic jam were analysed. Based on similarity law, a small-scale model tunnel including vehicle heat sources was set up. The air velocities only functioned by thermal pressure were tested out. A three-dimensional unsteady flow model was chosen. The temperature field and velocity field were simulated with Fluent software, its results were verified by experiment ones. Further sensitivity analyses including vehicle speed, shaft number and buried section length show that: thermal pressure but not traffic wind pressure is the main factor under traffic jam which influences the inside flow field; air velocities are nonuniform inside a buried section, and the midst of flow field is influenced little by shaft number for it is far away from the shafts on both sides; increasing length of a buried section leads to increase of its air velocities.