An experimental and kinetic modeling study on the autoignition characteristics of indene

摘要

Indene is an important intermediate in the ring growth process of polycyclic aromatic hydrocarbons(PAHs) which are soot precursors in the fuel combustion. Ignition delay times of indene/3.3 O_2 /Ar andindene/air mixtures were measured behind reflected shock waves over temperatures of 1098–1618 K,pressures of 2.5–10.0 atm, and equivalence ratios of 0.5, 1.0 and 2.0. An Arrhenius-type formula can describeall the measured indene/3.3 O_2 /Ar ignition delay data. But three Arrhenius-type formulas wereused to describe the measured indene/air ignition delay data for three pressures because the activationenergy varies with different ignition pressures. Indene ignition characteristics in different dilution conditionswere compared and discussed. Current results show that the indene ignition delay follows τ ∝Φ~(+n) diluted in Ar with fuel-lean mixture igniting the fastest and τ ∝ Φ~(?n) at real fuel-air condition withfuel-rich mixture igniting the fastest. For indene/air, when the pressure increases, the effect of equivalenceratio on ignition becomes stronger and the sensitivity of ignition to the variation of temperaturebecomes weaker. Furthermore, an indene combustion mechanism was developed. The predictions of thedeveloped mechanism are in good agreement with the measured data. Reaction pathway and sensitivityanalyses were carried out to determine reaction pathways during the ignition process and dominate reactionswhich affect ignition delay times. Current experimental results are useful for understanding theignition properties of indene and studying the formations of larger PAHs and soot. To our knowledge,experimental ignition delay times and a detailed combustion mechanism for indene are firstly reportedin this work.