Numerical Simulation and Experimental Measurements of Soot and Organic Nanoparticles in Opposed-Flow Diffusion Flames of Methane, Ethylene and Propane

In recent years attention of researchers has been focused on the combustion generated particles in order to have a deeper knowledge on their formation and develop combustion systems with higher efficiency and lower environmental impact [1,2]. Opposed-flow configuration allows to study behavior and sooting tendency of fuels, avoiding fluidodynamic problems fundable in diffusion flames laminar or turbulent. On the other hand, for co-flow flames, the study of particles inception and growth is much more complex than the opposedflow system because the co-flows are intrinsically two dimensional compared to a quasi-one dimensional opposed-flow [3]. Moreover, soot formation in opposed-flow diffusion flames has been extensively investigated because of its relevance to turbulent flames in the laminar flamelet model. In the present work, three different fuels: ethylene, methane and propane, in comparable conditions, have been investigated, experimentally and by numerical simulation. The experimental detection of combustion-byproducts is attempted by UV laser induced emission spectroscopy. The fourth harmonic of a pulsed Nd:YAG laser (266 nm) is used, in order to enhance fluorescence from molecular particles within the flame and also allows larger soot particles to heat up and emit incandescent radiation [4]. Modeling of particulate concentration is performed by using a detailed gas-phase chemical kinetics coupled with aerosol dynamical equations using a discrete size spectrum [6-8]. The Comparison of model results with laser induced emission signals, is proposed, in order to contribute to understanding of the process of particle inception and dynamic in diffusion controlled conditions.