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This article presents a detailed kinetic mechanism for the combustion of surrogate gasoline fuels (mixtures of primary reference fuels and toluene) that has been developed by modification of a previous mechanism (Andrae et al., 2007). The modifications introduced were: (i) revision of the sub-mechanisms associated with H2, CO and CH4 oxidation and (ii) retuning of rate coefficients of reactions involved in the i-octane oxidation sub-mechanism. The first set of modifications made use of new kinetic parameters evaluated by the CODATA project (Baulch et al. 2006), whereas the second was prompted by a sensitivity analysis of the mechanism obtained after implementation of (i). The resulting mechanism, which describes the low, intermediate and high temperature combustion regimes, is used to study pre-ignition of surrogate gasoline fuels. Comparison of the simulation data with experimental measurements over a wide range of conditions reveals a good agreement.

In this work, the spark-ignition (SI) of a methane/air mixture contained in a constant-volume chamber is investigated by numerical simulations. A cylinder-shaped vessel filled with a methane/air mixture containing two electrodes is used as simulation model. The impact of an electrical discharge at the electrodes on the surrounding gas is simulated, with detailed treatment of the ignition process involvig chemical kinetics, transport phenomena in the gas-phase and electrodynamical modeling of the interaction between spark and fuel/air mixture. For the calculations, a 2D-code to simulate the early stages of flame development, shortly after the breakdown discharge, has been developed. Computational results are shown for ignition of a methane air-mixture.

Growing interest in pollutant emission reduction has increased the importance of numerical simulations of spark ignition as a first step in IC engine combustion. In this work, we present simulations involving the coupling of flow, chemical reactions and molecular transport with the discharge processes. The main focus hereby is to investigate the early stages of the formation of a flame kernel in a two-dimensional, cylindrical geometry with electrodes. The computational results shown here include the initial shock-determined phase after the breakdown of the channel, but also the transition to flame propagation for a methane-air mixture.

Auto-Ignition is a phenomenon that occurs in many practical combustion processes (engine knock, ignition in rapid compression machines or shock tubes etc). For many purposes, the combustible mixture can be treated as uniform in space, allowing zero-dimensional modelling. Sometimes, however, non-uniformities in temperature or in pressure cause “hot spot” formation, having increased temperature with respect to the surrounding. Since ignition delay is highly temperature dependent, the hot spot will ignite much earlier than its surrounding, leading to space- and time-dependent processes governed by the superposition of chemistry, gas-dynamics, and transport. This paper presents mathematical models to simulate homogeneous and hot spot ignition in one-dimensional geometries by solution of the conservation equations using detailed chemistry and a multi-species transport model.