Lean Flammability Limit of Pure Hydrocarbon Fuels and Aviation Fuels

摘要

Alternative aviation fuels are emerging in the marketplace. The fire-safety properties of these fuels, however, are unknown. Especially, the flammability limit of fuel is a crucial parameter. The present work focuses on measurements of lean flammability limits of four pure hydrocarbon fuels which are n-heptane, iso-octane, n-decane and n-dodecane, as well as traditional and alternative aviation fuels, including Jet-A, HEFA, SIP and FT-S8. The lean flammability limits of these selected fuels were determined under specific initial temperatures and pressures. An experiment including a customized power supply system to generate sufficient spark energy for ignition near the flammability limits was built to measure the lean flammability limit of each fuel. As the initial temperature increases, the lean limit decreases. In terms of the fuel-air mass ratio, the lean limit is within the range of 0.033-0.04 for all four aviation fuels. Unlike temperature, pressure has a minor influence on the lean flammability limit of each fuel. Three correlations and models were used to predict the lean flammability limits of the four pure fuels. The predictions were compared to the measurements to evaluate how these models work for heavy hydrocarbon fuels.