Laminar Flame Speeds and Extinction Limits of Conventional and Alternative Jet Fuels

Abstract

*† § Atmospheric pressure laminar flame speeds are measured using a counterflow twinflame configuration for Jet-A/O2/N2 and S-8/O2/N2 mixtures at preheat temperatures of 400 and 470 K and equivalence ratios ranging from 0.8 to 1.4. The flow field is recorded using Digital Particle Image Velocimetry. Linear extrapolation is used to determine the unstretched laminar flame speed. Experimental data for the extinction stretch rates of the nitrogen diluted jet fuel/oxidizer mixtures as a function of equivalence ratio are also obtained. In addition, the experimental results for laminar flame speeds and extinction stretch rates for the conventional (Jet-A) and alternative (S-8) jet fuels are compared to the results from our earlier studies for neat hydrocarbon surrogate components, namely ndecane and n-dodecane. Furthermore, the experimental data of Jet-A are compared to the computed values using a chemical kinetic mechanism for a kerosene surrogate. A sensitivity analysis is also performed to identify the most sensitive reactions to laminar flame speed and extinction stretch rate.