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Re: Fire Chemistry Module
Posted by:
djicove (IP Logged)
Date: November 15, 2017 07:45PM
See: Haussmann, G. J., & Matta, L. M. (2002). Flammable Vapor Ignition by Engine Exhaust Systems. Journal of applied fire science, 11(4), 335-348.
ABSTRACT
Gasoline spills during the refueling of a hot engine creates a fire hazard.
A unique hot surface ignition mechanism has been discovered involving
exhaust systems on hot, shut down engines. The present research involves
small engines up to 45 hp that operate at relatively high tailpipe temperatures.
Although exhaust temperatures in excess of 700C were common,
external surfaces were found to be incapable of causing ignition for the
conditions studied. After engine shutdown, however, a buoyancy-driven
flow pattern was discovered in which gases enter the exhaust pipe. Heating
of flammable vapors drawn into the exhaust pipe resulted in ignition, even
though ignition was not possible on external surfaces. This ignition mechanism
exists when the tailpipe discharges upward or horizontally, but was
not observed in downward facing configurations. For ignition to occur by
this mechanism, an exhaust diameter of 3.8 cm or greater and a temperature
of 550C were required.