The effect of oxygen and carbon dioxide concentration on soot formation in nonpremixed flames using time resolved LII technique

Numerical and experimental study of the influence of CO2 and N2 dilution on soot formation in laminar coflow C2H4/air diffusion flames at pressures between 5 and 20 atm

“…Based on their numerical results Guo and Smallwood [12] concluded that the chemical suppression effect of CO 2 addition on soot formation is through reducing soot inception and surface growth rates, but not through enhancing soot oxidation associated with the enhanced OH radical concentrations suggested in earlier studies [3,[5][6][7][9][10][11]. The findings of Guo and Smallwood are consistent with the experimental measurements of Oh et al [10,11], who observed reduced soot number density in soot inception regions and smaller primary soot particle diameters. The primary pathway for the chemical effects of CO 2 was again found to be the reverse reaction of CO + OH M CO 2 + H, which reduces the H radical concentrations and consequently pyrene concentrations [12].…”

“…There have been several studies to investigate the influence of CO 2 dilution effects on soot formation in both counterflow and coflow diffusion flames at atmospheric pressure over the last five decades [3][4][5][6][7][8][9][10][11][12]. When a diluent is introduced to either the fuel side or the oxidizer side of a diffusion flame it influences the flame properties and pollutant formation through the following three mechanisms [5]: dilution, thermal, and chemical.…”

“…The dominant pathway for the chemical effect of CO 2 was identified to be the reverse reaction of CO + OH M CO 2 + H [9]. In their experimental studies of the effects of CO 2 addition to the oxidizer side on soot formation in a laminar coflow propane diffusion flame Oh et al [10,11] found that the chemical effects of CO 2 results in a lower primary particle number concentration in soot inception regions due to reduced flame temperature and increased OH concentration as a result of the reverse reaction of CO + OH M CO 2 + H. In addition, the primary soot particles are smaller. To gain further understanding of the nature of the chemical effects of CO 2 addition on soot formation, Guo and Smallwood conducted a numerical study to investigate how addition of CO 2 to the fuel side influences soot formation in a laminar coflow ethylene/air diffusion flame using detailed chemistry and a sophisticated soot model [12].…”

Carbonaceous Nanoparticle Layers Prepared using Candle Soot by Direct- and Spray-based Depositions

“…An experimental system has been developed to directly deposit the soot particles from candle flame, which is classified as a non-premixed burner (in others references, the term of diffusion flame are used) (Bescond et al, 2016;Oh and Shin, 2006;Wu et al, 2017). The set up simply utilizes semi-open glass tube (inner diameter = 47 mm, length = 199 mm) equipped with candle position control by utilizing smooth mechanical shifting by a syringe pump.…”

The investigation of CO2 effect on the characteristics of a methane diffusion flame

“…To have a better design for non-fossil fuel combustion system, well understanding the influence of mixing CO 2 with CH 4 is a good step forward. Many valuable contributions have been done in this area [7,8,18] and it is known that adding CO 2 causes soot suppression in the combustion process [4]. Yet, it is not precisely known under which procedure the soot level reduces [15].…”