Enhancement on a Skeletal Kinetic Model for Primary Reference Fuel Oxidation by Using a Semidecoupling Methodology

Abstract

A semidecoupling methodology for developing skeletal chemical kinetic models is presented and applied to construct an enhanced skeletal model for PRF (primary reference fuel) oxidation, which consists of 41 species and 124 reactions. The basic idea and the semidecoupling methodology are to consider the oxidation mechanism of alkane as two parts: a comprehensive part to describe detailed reaction processes of C0−C1 radicals and molecules as the 'core' and a skeletal part that couples the 'core' to control the ignition characteristics. Accounting for the major weakness in the existing skeletal models for PRF oxidation, the enhancement on the new skeletal model mainly focuses on the laminar flame speed and important species evolution while maintaining the precise ignition delay prediction of the previous models. The new PRF skeletal model is validated against various experimental data including shock tube, jet-stirred reactor, flow reactor, premixed laminar flame speed, and internal combustion engines over a wide range of temperatures, pressures, and equivalence ratios. The results show good agreement with the experimental data, indicating that the semidecoupling methodology and the new skeletal model are promising for various reactors and engine applications incorporated with a multidimensional computational fluid dynamics (CFD) model.

Development of a skeletal mechanism for diesel surrogate fuel by using a decoupling methodology

“…This makes it possible to integrate the diesel surrogate mechanism into multidimensional CFD models for engine combustion simulations. (6) Several mechanisms for n-heptane, iso-octane, and n-decane have been developed using the decoupling methodology in our previous work [33,34,44]. It has been shown that the predictions from the newly developed mechanisms exhibit reasonable agreement with measurements of ignition delay times, primary species concentrations, laminar flame speeds, and extinction strain rates in fundamental experiments, as well as the auto-ignition, combustion and emission behaviors in compression ignition engines.…”

“…[44]. The major low-temperature reaction pathways for iso-octane oxidation include H-atom abstraction reactions (R14-R16), iso-octyl radical (C 8 H 17 ) oxidation reaction (R17), isomerization reaction (R18), secondary O 2 addition reaction (R19), O 2 C 8 H 16 OOH releasing OH reaction (R20), and ketohydroperoxide (C 8 ket) decomposition reaction (R21).…”

A reduced toluene reference fuel chemical kinetic mechanism for combustion and polycyclic-aromatic hydrocarbon predictions

“…Experimental and kinetic studies have been conducted to study the oxidation processes of primary reference fuels (PRF, mixture of n-heptane and iso-octane) and detailed and reduced PRF mechanisms are available from the literature [4,8,[10][11][12][13][14][15][16][17][18][19]. The general oxidation reaction pathways proposed by Curran et al [10,11] have been adopted in many kinetic studies.…”

Experimental and numerical investigation of combustion in a hydrocarbon and gaseous oxygen fuelled rocket

“…Standard k-ε (SKE), in the equilibrium product mixture. In the flamelet model, a chemical kinetic mechanism comprising of 41 species and 124 reactions for n-heptane was used [29].…”