reply to post by turbofan
Jet fuel doesn't explode when falling down a shaft!
Never mind that; the amount of jet fuel available could not have expanded
through 1000+ feet of elevator shaft to produce enough pressure to blow
off marble slabs from the lobby walls.
Wow ! A truther spouting off about something they know nothing about!
From CAL TECH Explosion Dynamics Laboratory
www.galcit.caltech.edu...
Flammability limits refer to the range of compositions, for fixed temperature and pressure, within which an explosive reaction is possible when an
external ignition source is introduced. This can happen even when the mixture is cold. Flammability limits are given in terms of fuel concentration
(by volume) at a specified pressure and temperature. For example, the lean flammability limit for Jet A (aviation kerosene) in air at sea level is a
concentration (by volume or partial pressure) of about 0.7%. The rich flammability limit is about 4.8% by volume or partial pressure. Flammability
limits are not absolute, but depend on the type and strength of the ignition source. Studies on flammability limits of hydrocarbon fuels have shown
that the stronger the source of the ignition stimulus, the leaner the mixture that can be ignited. Flammability limits also depend on the type of
atmosphere (for example, limits are much wider in oxygen than in air), the pressure, and the temperature of atmosphere.
Jet fuel has a flammable range of .7% to 4.8% - that percent of fuel
mixed with air will ignite and burn
Operative phrase - "explosive reaction possible"
Flammability limits refer to the range of compositions, for fixed temperature and pressure, within which an explosive reaction is possible when an
external ignition source is introduced.
Explosive limits
Explosion limits usually refer to the range of pressure and temperature for which an explosive reaction at a fixed composition mixture is possible.
The composition has to be within the flammable range. The reaction is usually initiated by autocatalytic (sometimes called self-heating) reaction at
those conditions, without any external ignition source. In practical terms, this means that the mixture needs to be sufficiently hot. Explosion limits
are given in terms of a minimum autoignition temperature (AIT) for ignition of fuel injected into hot air. The minimum AIT is strong function of the
fuel type (atomic composition and molecular structure), pressure, and fuel concentration. For common hydrocarbon fuels, the minimum AIT ranges between
600C (1350 F) for methane (CH4) to 200C (472F) for dodecane (C12H26). A minimum AIT of 190C (450F) is used for the purposes of hazard analysis for
aviation kerosene. Note that the minimum AIT is much higher than the flash point and much lower than typical hot surface ignition temperatures, which
can be as high as 900C (2000F) for common hydrocarbon fuels (Smyth, K. C.; Bryner, N. P. Combustion Science and Technology, Vol. 126, 225-253,
1997).
So a mixture of Jet Fuel in the flammable range exposed to temperature
of 190C (450F) will explode
Detonation
Detonation limits are the range of composition within which detonations have been observed in laboratory and field experiments. Detonation limits are
a strong function of mixture composition, initial pressure and temperature but usually considered to be narrower than the flammabilty limits. In
addition, detonation limits are much more strongly dependent on the ignition source, confinement, and the physical size of the experiment than
flammability limits. The ability to initiate and propagate a detonation requires a set of critical conditions to be satisfied and despite extensive
research into the subject, the limits are empirical in nature.
Under proper conditions an explosive mix will detonate
The jet fuel falling down the elevator shaft will be accelerated by gravity,
air resistance will break the fuel stream up into droplets. The long fall
will disperse the fuel droplets as an aerosol and mix it with air. All
you need is ignition source...
You lose!
