Numerical Investigation on the Effect of Fixed and Movable Smoke Exhaust in Subway Tunnel Fire

In this paper, a numerical study was carried out to analyze the smoke exhaust effect under different patterns. Fixed, movable, fixed-movable combined patterns and various settings in each pattern are taken into account. Smoke spread and tunnel ceiling temperature are the main characteristics of smoke exhaust effect. Results show that under normal operating condition of fixed pattern, the smoke spread in the upstream of the fire source can be suppressed. Under the fixed-movable combined pattern, the addition of the movable fan further produces a cooling effect on the downstream of the fire source, which is helpful to maintain the temperature downstream below the safe temperature threshold. In the movable smoke exhaust pattern, the influences of the inclined angle of the movable fan and the distance from the fire source are related to the air volume of the moving fan. When applying the arrangement pattern of movable fans in series, compared with increasing the number of movable fan of the same specification, increasing the ventilation volume of movable fan has a more significant effect on reducing the temperature in the tunnel.