Experimental Investigation on the Distribution of the Mass Flow Rate of Fire Smoke in a Longitudinally Ventilated Tunnel

To study the influence of the longitudinal ventilation on the mass flow rates of the fire smoke in the tunnel, several experiments have been conducted in a reduced-scale model tunnel (with a scale of 1/3). During the experiments, the variations of the mass flow rates of the fire smoke are deduced by the measured ceiling temperatures instead of being directly recorded. It concludes that the mass flow rates of the fire smoke are influenced by the longitudinal air flow. When the dimensionless longitudinal velocity is not larger than 0.19, the mass flow rates of the tunnel fire smoke at the upstream side and the downstream side are equals to each other and keep unchanged. When the dimensionless longitudinal velocity grows larger than 0.19, the two parameters begin to change and are no longer equal.