The Influence of Air Curtains on Fire Smoke in Tunnels

Abstract

To figure out the influence of smoke-proof air curtains on the law of tunnel fire smoke spread, this paper set a simulated fire scene of passenger bus with a fire source power of 25 MW in Fire Dynamics Simulator (FDS), a software for stimulating fire dynamics, to study the law of fire smoke spread in tunnels. At first, this paper analyzed the distribution of smoke temperature, visibility, and CO concentration in each area of the tunnel under the conditions of different jet velocities and angles of the air curtain, and explored the influence of air curtain on the law of fire smoke spread in the tunnel. The research results showed that, when the fire source power was 25MW and the smoke exhaust rate was 100m3/s, in order to effectively control the spread of smoke, the jet velocity of the air curtain should not be less than 7m/s. With the increase of jet velocity, the smoke-proof effect of the air curtain exhibited a trend of increasing first and decreasing later, and the optimal effect was reached at a jet angle of 20°. The influence of jet velocity on the smoke-proof effect was more significant, in case of a fire source power of 25MW and a smoke exhaust rate of 100m3/s, after comprehensively considering the effect and economy of smoke-proof, it’s determined that the best smoke-proof effect could be achieved under the conditions of a jet velocity of 10m/s, and a jet angle of 20°. Our research results proposed reasonable parameters for the smoke-proof of air curtain, which had improved the economy and provided useful guidance for smoke-proof in tunnels.