Ignition Characteristics of Alternative Jet Fuels under Vitiated Conditions

Abstract

Atmospheric pressure flow reactor experiments were performed to investigate the ignition characteristics of Fischer-Tropsch and hydrotreated renewable JP-8 fuels under vitiated conditions in order to compare these properties to conventional JP-8. Ignition experiments were conducted with reactor temperatures between 832 K and 917 K with standard air as well as vitiated air with 17% O 2 and NO x levels varied between 0 and 755 ppmv. Experiments were also performed with jet fuel surrogate components such as n-dodecane and iso-octane to investigate the ignition behavior of normal-and iso-paraffins, respectively. Experimental measurements show that the presence of NO x in the oxidizer stream reduces the ignition delay time of jet fuels and surrogates significantly. Furthermore, the effect of NO x on iso-octane ignition delay time is more pronounced than for n-dodecane. Surrogate kinetic modeling results are also compared with the experimental data regarding the effect of NO x . Overall, the modeling results agree with trends observed for the effect of NO x on ignition delay time. However, the ignition delay time predictions for Sasol-IPK are much longer than the experimental data. This is due to the fact that the representation of isoparaffinic components in Sasol-IPK is not correctly represented by iso-octane alone.

Experimental and Modeling Study of C1–C3 Hydrocarbon Ignition in the Presence of Nitric Oxide

“…The presence of NO x (NO and NO 2 ) in the oxidizer stream occurs in various practical devices where combustor design includes exhaust (or flue) gas recirculation (e.g., internal combustion engines and furnaces), vitiated air (e.g., gas turbine exit streams, and high-speed propulsion test rigs), and internal recirculation zones (e.g., gas turbines). Previous works by the authors [3][4][5] showed that NO x plays a significant role in promoting ignition of jet fuels and its surrogate components. Experimental and direct numerical simulation studies of Lee et al [6] have demonstrated the importance of NO on the reignition process of a vortex-perturbed counter flow flame.…”