Experimental Study of Scale Effect in Tunnel Fires at Different Sealing Ratios

Fully or partially sealing the openings of tunnels to accelerate self-extinction fires provides a promising firefighting tactic beat large in long tunnel. So far, most experimental studies on characteristics fire with different ratios have been conducted reduced-scale tunnels. However, whether findings tunnel can be converted its full-scale prototype based scaling laws has not yet adequately studied. A series experiments heat-release rates 15.8, 31.6 and 63.2 kW were ranging from 0% 100% measuring 20 m long, 0.9 wide 0.46 high. The results compared those 1/2 10 0.45 0.23 It showed that temperature rise along reduced-tunnel could significantly underestimated. differences increased monotonously distance away seat, they as high 70% at portals, irrespective ratios. study scale effect was sensitive Reynolds number flows minimal ratio for 85%, whilst it 75% tunnel, revealed much easier extinguish than where sustain lower oxygen concentration. demonstrated invalid observed should further verified when applied prototypes.