Abstract: In order to compare the smoke exhaust effect of ceiling mechanical smoke exhaust and lateral mechanical smoke exhaust in tunnel fire, the temperature distribution, velocity vector field distribution, smoke output, heat output, and smoke exhaust efficiency of the two smoke exhaust methods in tunnel fire were numerically simulated. The results show that the velocity vector field distribution and the smoke inhalation method of the two smoke exhaust methods are quite different. The ceiling mechanical exhaust has higher smoke exhaust volume and exhaust heat, and the exhaust effect is better; The lateral mechanical smoke exhaust is more likely to occur plug-holing and cause the fresh air drawn directly into the smoke exhaust system, and its smoke exhaust efficiency is always less than that of the ceiling mechanical smoke exhaust.

Key words: ceiling mechanical smoke exhaust, lateral mechanical smoke exhaust, tunnel fire, plug-holing