Figure 1
Left, large-scale pool. Right, small-scale tubes, circular A) and rectangular B).
Figure 2
(a) Pool filled with foam and covered with foil; (b) Pool filled with foam and removed foil; (c) Snapshot after ignition. (d) Empty pool with open foam generator. (e) Empty pool with sintered plate covered foam generator and obstacle lines. (f) Snapshot from high-speed video (2000 f/s).
Figure 3
Small-scale vertical tube facility. (a) Rectangular thin layer configuration; (b) Snapshot from high-speed video, rectangular thin layer; (c) Circular tube configuration during foam filling; (d) Snapshot from high-speed video, circular tube.
Figure 4
Left, example of foam density vs. run-time of foam generator for different gas-flow rates. Center, example of foam density vs. run-time of foam generator for gas-flow rate (10 dm3/min) for different extinguisher agent concentrate. Right, picture of extinguisher foam (2% extinguisher agent concentrate; gas-flow rate 10 dm3/min).
Figure 5
Foam density. Left, average foam density in the small-scale circular tube vs. foam agent concentration. Right, example of foam density distribution in large-scale pool.
Figure 6
Left, snapshot from the high-speed movie (2000 f/s) at the time of ignition. Right, stack montage from the high-speed movie as distance-time diagram (25% H2 firefighter extinguisher foam 0.5%).
Figure 7
The picture series high-speed movie (25% H2 firefighter extinguisher foam; time step between frames = 6 ms).
Figure 8
Stack montage from the high-speed movie (4000 f/s) as distance-time diagram. (Small transparent channel (d = 90 mm); family bubble bath 1%). Left, 23% H2; Right, 40% H2.
Figure 9
Run-up-distance (x) of the flame up to the hot-spot point inside the transparent channel (d = 90 mm) for the bubble bath and fire extinguisher foams.
Figure 10
Flame propagation velocities in family bubble bath (Left) and the fire extinguisher foam (Right).
Figure 11
Speed of sound in the foams.
Figure 12
Left, stack montage from the high-speed movie (4000 f/s) with signals of the three pressure gauges. Right, maximum overpressure vs. H2-concentration in the fire extinguisher foam 0.5%.
Figure 13
Picture series of the combustion of a family bubble bath foam (2%) inside the rectangular (cross section of 0.02 m × 0.2 m) vertical 2 m high channel (50 vol.% H2 in O2; 10000 f/s).
Figure 14
Low flame propagation velocity measured in this study.