Characterization of Particles formed in Methane and Ethylene Opposed-flow Diffusion Flames

In the this work an experimental and numerical study on particles formation in opposed-flow diffusion flames, burning methane and ethylene as fuel is presented. Spectrally resolved laser induced emission spectroscopy techniques in the ultraviolet and visible, such as fluorescence and incandescence, are here used in order to investigate particles inception and growth with high spatial resolution and in a wide range of flame conditions. The fourth harmonic of a Nd:YAG laser, 266 rim, is used with the purpose to follow combustion generated compounds and their dynamics in flame. A complete kinetic scheme, which provides both to gas-phase and particle reactions, is adopted for numerical simulation. The comparison between experimental results and numerical predictions gives a qualitative view of the mechanism of particle formation.