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chapter 5 turbulent diffusion flames - FedOA

chapter 5 turbulent diffusion flames - FedOA

C/O=0,56 Non Non --

C/O=0,56 Non Non -- sooting sooting C/O=0,77 Slight Slight -- sooting sooting 22 C/O=0,92 Sooting Sooting Fig. 1.3 3D AFM images for three different laminar premixed ethylene flames conditions from: Barone et al. [33].

1.3 SOOT FORMATION, GROWTH AND OXIDATION As showed by Dobbins and Subramaniasivam [28] and by Vander Wal [29] by transmission electron microscopy analysis (TEM) of thermophoretic sampled material, soot is normally composed by aggregates of hundred or thousand of primary particles with mean size of 10 – 30 nm that form structures 0.1 µm up to10 µm. (Fig. 1.4) Fig. 1.4 TEM image of a typical soot aggregate by Dobbins and Subramaniasivam [28]. Theoretically, after the early numerical modeling work in PAH and soot formation based on the HACA mechanism, Frenklach and Wang extended and refined the model description of soot nucleation and growth applying it to laminar premixed acetylene and ethylene flames under different pressures [34] for which experimental data where available. The computational model used for the prediction of soot formation consisted of three logical parts: (I) initial PAH formation, which includes a detailed chemical description of fuel pyrolysis and oxidation, formation of the first aromatic ring, and its subsequent growth to a prescribed size; (II) planar 23

DNS of Turbulent Nonpremixed Ethylene Flames
Heat release rate measurement in turbulent flames