Thirdly, although hydrogen has flammability limits
of 4-75%, its explosive limits are different at 17-56%, and its very low vapour density means it will tend to dissipate harmlessly into the atmosphere (look at hydrogen vehicle fires online and see how well they compare to petrol!).
N., "Flammability Limits
: An Invited Review," Combustion and Flame, Vol.
Caption: FIGURE 3 Classes of refrigerant flammability comparing the lower flammability limits
(LFLs) and burning velocity (BV) for various refrigerants.
This configuration results in the widest flammability limits
possible because the buoyancy of the hot gases assists flame propagation up the tube.
The combustion characteristics were represented through the flame visualization, flammability limits
, and flame temperature.
The rich and lean flammability limits
for pure compounds cited in the literature, e.g.
Figure 2 shows a comparison between flame propagation limits measured with the 40 mm (1.6 in.) diameter vertical tube and flammability limits
measured with a 12 L (0.42 [ft.sup.3]) flask as specified in ASHRAE Standard 34 (2010).
The minimum ignition energies (MIE) are generally higher, the lower flammability limits
(LFL) are generally higher and the heats of combustion (HOC) are generally lower.
Another important parameter is the ratio of flammability limits
. In the combustor, the fuel and air must be continually burned to keep the engine running.
This time duration has been proved to be the most appropriate for flammability limits
measurements (Kondo et al.