Citation

Vaivads RH, Bardon MF, Battista V. Fire Safety J. 1997; 28(4): 307-322.

Copyright

(Copyright © 1997, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The fire hazards associated with gasoline and methanol are different because of the different physical and chemical properties of the fuels. In particular, the composition of the vapors they emit determines the comparative risk of a fire or explosion in cases of accidents or fuel leaks. This study compares the behavior of methanol and gasoline (n-octane) using mathematical models, so as to assist in determining whether there is an increased risk associated with the use of methanol fuels. The flammable zones surrounding a representative unconfined exhaust manifold were determined for methanol and n-octane at two manifold surface temperatures (700 and 1000 K) using computational fluid dynamics (CFD) techniques. Some of the CID computations were also confirmed experimentally. It was found that for a manifold surface temperature of 700 K, neither fuel would ignite, although the surface temperature is above the autoignition temperature for both fuels. At a surface temperature of 1000 K, it was found that each fuel could ignite and that this temperature would be near the minimum required for either fuel to be ignited by a hot surface. The predictions also confirm the experimentally observed phenomenon that real hot surface ignition temperatures are, generally, well above autoignition temperatures. It was concluded that the risk of spontaneous ignition is similar for both fuels for the type of leak scenario investigated (i.e. the risk with methanol is not significantly different than that of gasoline). The use of two-dimensional (2-D) steady-state CFD simulations can provide significant insight into the behavior of different fuels in what is generally a three-dimensional (3-D) transient phenomenon.