Simulations of Temperature and Smoke Distributions of Fires in a Road Tunnel with Roof Openings

To interpret the characteristics of smoke flow in a road tunnel with roof openings, numerical simulations were conducted by using CFD software FDS4.07 version. Also the predicted results were compared with the experimental data of a full scale experiment in a literature. With aiming at the engineering application, the software FDS can provide reliable predictions. Then various velocities varying from 1.0 m/s to 3.0 m/s of natural wind under the same fire were simulated numerically. It was found that with an increase on the wind velocity from 1.0 m/s to 3.0 m/s, the length of the back flow was reduced from 105.0 m to 75.0 m. And the various velocities did not have significantly different effect on smoke longitudinal propagation at the early and decay stage of the fire development. Under the different velocities the gas temperature at safety height 1.8 m could not pose a threat on the life covering 300 m from fire source downstream.