A Reduced Chemical Kinetic Mechanism for Toluene Reference Fuels Based On DRGEP and QSSA Methods

Abstract

As a gasoline surrogate fuel, the physical and chemical properties of toluene reference fuel (TRF) are relatively simple and stable, and the TRF chemical kinetic mechanism may be used in simulating combustion processes of gasoline. However, simulations using detailed or semi-detailed mechanisms have been limited due to the computational complexity and long computational time. For the construction of the reduced mechanism, the directed relation graph with error propagation (DRGEP) method is used to wipe out insignificant components efficiently, followed by the use of the quasi-steady state assumption (QSSA) method to separate quasi-steady-state (QSS) species from the kinetic ODEs. In addition, some elementary reactions involving the formation and destruction of H and phenyl methyl radicals are subjected to sensitivity analysis and some kinetic parameters of the relevant elementary reactions are revised. As a result, a reduced mechanism involving 234 reactions and 60 species is developed. Comparing the experimental records with the analog data by utilizing the reduced mechanism, good agreement can be obtained when ignition delay time (τ), laminar flame speed (SL) and molar fraction of vital species are measured. Moreover, the mechanism may predict SL more accurately under lean mixture (equivalence ratio φ < 1.0) conditions. The reduced mechanism is small and reliable in performance, which can commendably reproduce the combustion characteristics of gasoline surrogate.