Abstract: In order to explore influence of water curtain smoke exhaust system on smoke control and exhaust efficiency in tunnels, smoke spread, temperature and velocity distribution were studied for different smoke exhaust volume by utilizing fire dynamics solver (FDS). The results show that water curtain can't effectively block spread of toxic smoke when the exhaust volume is less than 100 m³/s. And in cases of 10, 20 and 30 MW for heat release rate and 100, 160 and 180 m³/s respectively for smoke exhaust volume, smoke can be contained the water curtain system. With help of water curtain, temperature distribution outside it can meet needs of people to escape (less than 80 ℃), and smoke control is more important than temperature control in the system. While at the same fire source heat release rate(HRR), smoke exhaust efficiency of vents increases first and then decreases along with smoke volume. Moreover, suction effect of vents is difficult to form, and the main reason for low smoke exhaust efficiency is that smoke inhaled by vents at bottom of tunnels is mixed with a lot of fresh air.

Key words: water curtain smoke exhaust system, tunnel fire, smoke control, temperature distribution, smoke exhaust efficiency