Experimental and Kinetic Modeling of Kerosene-Type Fuels at Gas Turbine Operating Conditions

Abstract

Experimental and kinetic modeling of kerosene-type fuels is reported in the present work with special emphasis on the low-temperature oxidation phenomenon relevant to gas turbine premixing conditions. Experiments were performed in an atmospheric pressure, tubular flow reactor to measure ignition delay time of kerosene (fuel–oil No. 1) in order to study the premature autoignition of liquid fuels at gas turbine premixing conditions. The experimental results indicate that the ignition delay time decreases exponentially with the equivalence ratio at fuel-lean conditions. However, for very high equivalence ratios (>2), the ignition delay time approaches an asymptotic value. Equivalence ratio fluctuations in the premixer can create conditions conducive for autoignition of fuel in the premixer, as the gas turbines generally operate under lean conditions during premixed prevaporized combustion. Ignition delay time measurements of stoichiometric fuel–oil No. 1∕air mixture at 1 atm were comparable with that of kerosene type Jet-A fuel available in the literature. A detailed kerosene mechanism with approximately 1400 reactions of 550 species is developed using a surrogate mixture of n-decane, n-propylcyclohexane, n-propylbenzene, and decene to represent the major chemical constituents of kerosene, namely n-alkanes, cyclo-alkanes, aromatics, and olefins, respectively. As the major portion of kerosene-type fuels consists of alkanes, which are relatively more reactive at low temperatures, a detailed kinetic mechanism is developed for n-decane oxidation including low temperature reaction kinetics. With the objective of achieving a more comprehensive kinetic model for n-decane, the mechanism is validated against target data for a wide range of experimental conditions available in the literature. The data include shock tube ignition delay time measurements, jet-stirred reactor reactivity profiles, and plug-flow reactor species time–history profiles. The kerosene model predictions agree fairly well with the ignition delay time measurements obtained in the present work as well as the data available in the literature for Jet A. The kerosene model was able to reproduce the low-temperature preignition reactivity profile of JP-8 obtained in a flow reactor at 12 atm. Also, the kerosene mechanism predicts the species reactivity profiles of Jet A-1 obtained in a jet-stirred reactor fairly well.

OH time-histories during oxidation of n-heptane and methylcyclohexane at high pressures and temperatures

“…The Biet et al [65] n-heptane mechanism (not validated at high-temperature conditions) has been generated using the EXGAS software, a computer package developed to perform the automatic generation of detailed kinetic models for the gas-phase oxidation and combustion of alkanes. The Gokulakrishnan et al [66] kerosene mechanism includes n-heptane (the n-heptane sub-mechanism is a skeletal mechanism Table 2 Summary of current high-pressure OH absorption experiments. derived from the Curran et al [61]) and was validated for ignition delay times.…”

“…We have compared our OH species measurements with the predictions of three MCH mechanisms (Pitz et al [12], Orme et al [24], and Ranzi [57]) and 11 n-heptane mechanisms (Ranzi [ [66], and Golovitchev [67]) as listed in Table 1. The mechanisms discussed here have been developed and optimized to address particular needs and applications, and have not, in particular, been optimized to accurately simulate OH timehistories.…”

“…However, the importance of the small radical pool (H, O, HO 2 , OH, and CH 3 ) to all ignition processes implies that these mechanisms should realistically be expected to model OH profiles accurately. [57] MCH, n-heptane 2006 280 7800 You et al [58] n-Heptane 2008 177 1318 Chaos et al [59] n-Heptane 2007 107 723 Seiser et al [60] n-Heptane 2000 160 1540 Curran et al [61] n-Heptane 1998 560 2539 Tsang [62] n [65] n-Heptane 2008 119 970 Gokulakrishnan et al [66] n-Heptane 2007 554 1398 Golovitchev [67] n-Heptane 2000 102 520…”

Ignition Characteristics of Alternative Jet Fuels under Vitiated Conditions

“…The current detailed reaction mechanism is based on an improved version of the surrogate kinetic model previously reported by authors that primarily consists of n-decane (n-C 10 H 22 ), n-propylcyclohexane (C 9 H 18 ), and n-propylbenzene (C 9 H 12 ) to represent paraffins, naphthenes and aromatics, respectively [14]. In the current model, additional surrogate components, namely, n-dodecane (n-C 12 H 26 ) and isooctane (i-C 8 H 18 ) are included to better represent the normal-and iso-paraffin components, respectively, that are present in typical jet fuels, including the alternative fuels shown in Figure 5.…”

Reduced Kinetic Models for the Combustion of Jet Propulsion Fuels

“…ORMULATION methodologies of appropriate surrogate mixtures that emulate the combustion behaviors of a real aviation fuel have been extensively investigated by various approaches in the last decade [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Recently, it has been demonstrated that successful surrogate mixtures for the emulation of combustion kinetic behaviors can be formulated by matching select physical and chemical properties of a targeted fuel [12][13][14].…”