Abstract
The mission was to identify the conditions of atmospheric pressure and ambient temperature under which a so- called empty-fuel-tank, containing residual fuel, could contain hazardous airlfuel mixtures. The issues are limited to two applications: terrestrial vehicle emissions reduction, and, explosion safety concerns in automotive vehicles and aerospace.
In general, we conclilded that flammable mixtures, under certain conditions, may exist in an empty fuel tank containing resldual fuel, at ambient temperatures ranging from minus -51° C (-6d' F) through 93" C (20d' F), at or below atmospheric pressure Furthermore, at normal ambient temperatures, it is certain that an over-rich mixture may exist in an automotive fuel tank, and this fact permits the vapor to be applied to reduce the cold start portion of exhaust emissions. On-the-other-hand, it is highly unlikely that a combustible mixture could exist in ajet aircraft fuel tank at ambient temperatures below 38'C (10d'F) which is the lean limit flash point for jet fuel. Never the less, this study identified three highly unlikely, but rationally possible scenarios which may permit a combustible mixture to exist within a jet aircraft fuel tank and pose a potential hazard.