Assessment of soot formation models in lifted ethylene/air turbulent diffusion flame

Abstract

In the present study, soot formation in the turbulent lifted diffusion flame, consisting of ethylene-air is numerically investigated using three different soot modeling approaches and is comprehensively reported.For turbulence-chemistry interaction, Flamelet generated manifold (FGM) model is used. A detailed kinetics is used which is represented through POLIMI mechanism (Ranzi et al. 2012). Soot formation is modeled using two different approaches, semi-empirical two-equation approach and Quadrature methods of moments approach, where both the approaches consider various sub-processes such as nucleation, coagulation, surface growth and oxidation. The radiation heat transfer is taken into account considering four fictitious gasses in conjunction with the weighted-sum-of-gray gas (WSSGM) approach for modeling absorption coefficient. The experimental and earlier published numerical data from Köhler et al. (2012) and Blacha et al. (2011) are used for assessment of different soot modeling approaches. The discrepancies between numerical and experimental data are observed due to under-prediction of OH radicals 1 Corresponding author, Ashoke De 2 concentration and poor fuel-air mixing ratios in the vicinity of the fuel jet region leading to early soot formation and the trends are unaffected after invoking radiation.

Large-Eddy Simulation and analysis of a sooting lifted turbulent jet flame

“…In steady-state simulations of the SLTJF, a high sensitivity of soot formation to the correct prediction of fuel and air mixing is observed [15,[20][21][22]. This holds for other sooting jet flames, too.…”

Soot production modelling for operational computational fluid dynamics fire simulations

“…Soot production is modelled with the three combinations of soot models described above (Delichatsios' formation together with Lee's, Beji's and Chen's oxidation). In all three cases, Wang's fire is simulated with and without the temperature and composition adjustment, equation (9).…”

“…Before computing the soot volume fraction, the parameters of equation (9) are numerically calibrated, taking a reference value of 2.5 mm as the minimum cell size. This size was determined by tracking the temperature at the centre of a point located in the flame and the way its value changed as the cell size was reduced ( Figure 5).…”

Particulate Matter Produced by Micro-Scale Biomass Combustion in an Oxygen-Lean Atmosphere

“…For the description of this mechanism, a basic chemical and physical frame was created. In the chemical frame, the main precursor of soot formation is considered to be acetylene C 2 H 2 that is reacting to create higher hydrocarbons (aromatics with one or two rings) that are the basis of PAH [19]. Once the PAH is formed, the physical frame can be used to describe the rest of the formation.…”

“…Once the PAH is formed, the physical frame can be used to describe the rest of the formation. This consists of four steps: formation (nucleation), coagulation, condensation, and surface growth [19]. Coagulation and condensation are shown in Figure 1.…”