Experiment and Numerical Simulation on Natural Ventilation for Transportation Tunnel with Shafts Under Traffic Jam

摘要

Based on the current researches on the natural ventilated urban transportation tunnel with shafts, fluid flowing characteristics under traffic jam were analyzed and problems were pointed out. According to similarity laws, a small-scale model tunnel was set up including vehicle heat sources. Air velocities were tested out functioned only by thermal pressure. A three-dimensional unsteady flow numerical model was chosen. Temperature and velocity field were simulated with Fluent software. Its velocities of three identical positions were verified by that of experiments. Further sensitivity analyses including vehicle speed, shaft number, and buried section length show that under traffic jam, thermal pressure is a main factor which influences its inside flow field while not traffic wind pressure; air velocities are non-uniform inside a buried section, and the flow field of its midst is influenced little by shaft number for it being far away from adjacent shafts; increasing length of a buried section contributes to its increased air velocities.