TY - JOUR
T1 - The effect of oxygen concentration in the co-flow of laminar ethylene diffusion flames
AU - Sun, Zhiwei
AU - Dally, Bassam
AU - Alwahabi, Zeyad
AU - Nathan, Graham
N1 - Generated from Scopus record by KAUST IRTS on 2022-09-12
PY - 2020/1/1
Y1 - 2020/1/1
N2 - This paper reports an experimental study of the effects of oxygen concentration (OC) in the oxidant stream on the characteristics of laminar co-flow ethylene diffusion sooting flames. Oxygen concentration was varied from 16.8% to 36.8% (by volume) by either diluting the air co-flow with nitrogen or by adding oxygen. Planar optical measurements were performed, with high spatial resolution, of flame luminosity at 700 nm, soot volume fraction, flame temperature, primary soot particle diameters and OH* chemiluminescence. All measured parameters are found to vary significantly with OC over the investigated range. The soot volume fraction measurements quantify the extent to which soot formation and oxidation are enhanced by increasing OC, revealing that the former effect dominates in the upstream region, while the latter effect dominates the downstream region, close to the flame tip. The changes to flame luminosity, soot volume fraction and flame temperature are strongly correlated with each other, while the primary soot particle diameter correlates well with the soot residence time. In addition, the rate of soot evolution, including its formation and oxidation, correlates with flame temperature along the axis of flames and a second reaction zone emerges in the tip of flames with high OC, as revealed by OH* chemiluminescence. The experimental data are well suited to the development and validation of soot models because of the well-defined boundary conditions, high spatial resolution, systematic nature and combination of the measured scalars.
AB - This paper reports an experimental study of the effects of oxygen concentration (OC) in the oxidant stream on the characteristics of laminar co-flow ethylene diffusion sooting flames. Oxygen concentration was varied from 16.8% to 36.8% (by volume) by either diluting the air co-flow with nitrogen or by adding oxygen. Planar optical measurements were performed, with high spatial resolution, of flame luminosity at 700 nm, soot volume fraction, flame temperature, primary soot particle diameters and OH* chemiluminescence. All measured parameters are found to vary significantly with OC over the investigated range. The soot volume fraction measurements quantify the extent to which soot formation and oxidation are enhanced by increasing OC, revealing that the former effect dominates in the upstream region, while the latter effect dominates the downstream region, close to the flame tip. The changes to flame luminosity, soot volume fraction and flame temperature are strongly correlated with each other, while the primary soot particle diameter correlates well with the soot residence time. In addition, the rate of soot evolution, including its formation and oxidation, correlates with flame temperature along the axis of flames and a second reaction zone emerges in the tip of flames with high OC, as revealed by OH* chemiluminescence. The experimental data are well suited to the development and validation of soot models because of the well-defined boundary conditions, high spatial resolution, systematic nature and combination of the measured scalars.
UR - https://linkinghub.elsevier.com/retrieve/pii/S0010218019304377
UR - http://www.scopus.com/inward/record.url?scp=85072782229&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2019.09.023
DO - 10.1016/j.combustflame.2019.09.023
M3 - Article
SN - 1556-2921
VL - 211
SP - 96
EP - 111
JO - Combustion and Flame
JF - Combustion and Flame
ER -