Investigation on smoke temperature distribution in a double-deck tunnel fire with longitudinal ventilation and lateral smoke extraction

Abstract

A set of experiments is carried out in a 1/15 reduced-scale double-deck tunnel to investigate the effect of longitudinal ventilation and lateral smoke extraction on the temperature distribution. The factors of the longitudinal ventilation velocity and the location of fire source are considered under the heat release rate (HRR) of 23 kW. The thermal behavior of the tunnel is observed. The experimental results show that the upstream ceiling temperature decreases with the increase of longitudinal ventilation velocity, while the downstream ceiling temperature increases with the increase of longitudinal ventilation velocity. With the increasing of distance away from fire source, the dimensionless smoke temperature rise reduces exponentially along the tunnel ceiling. The upstream or downstream temperature of the upper tunnel at the location with the same distance away from the fire source is higher than that of the lower tunnel, and the maximum temperature difference can be reached 93 °C. With the longitudinal ventilation velocity at 0.516 m/s, the downstream smoke layering length are 8.35 m and 7.65 m longer than the upstream smoke layering length in the upper and lower tunnel, separately.