The combustion kinetics of a synthetic paraffinic jet aviation fuel and a fundamentally formulated, experimentally validated surrogate fuel

Abstract

A surrogate fuel is formulated in an a priori manner through a combustion property matching technique to emulate the gas phase chemical kinetic combustion phenomena of S-8 POSF 4734, an alternative aviation fuel derived from natural gas via the Fischer–Tropsch process. A fundamental concept is described which identifies n-dodecane and iso-octane as being appropriate surrogate fuel components for the non-aromatic synthetic fuels. The performance of the formulated 51.9/48.1mole % n-dodecane/iso-octane mixture as a surrogate for the target real fuel is evaluated by the measurement of a series of combustion phenomena exhibited by both fuels including:(1)The oxidative reactivity of stoichiometric mixtures of each fuel in O2/N2 at 12.5atm and 500–1050K, for a residence time of 1.8s at a fixed carbon content of 0.3% using a variable pressure flow reactor.(2)The autoignition behavior of stoichiometric mixtures of each fuel in air at compressed conditions of 667–1223K and ∼20atm by the reflected shock technique.(3)The strained extinction limits of diffusion flames of each fuel at 1atm.The performance of available kinetic models for n-dodecane/iso-octane mixtures is evaluated by analysis of their computations of this experimental data. Furthermore, the impact of oxidation kinetics unique to the mono methylated alkanes which are the dominant molecular structure in synthetic fuels is examined by an experimental study involving the formulation of an n-decane/iso-octane mixture as a surrogate fuel for 2-methyl heptane, a proposed model molecule for such real fuel components.