TY - JOUR
T1 - Effect of burner geometry on swirl stabilized methane/air flames: A joint LES/OH-PLIF/PIV study
AU - Liu, X.
AU - Elbaz, Ayman M.
AU - Gong, C.
AU - Bai, X.S.
AU - Zheng, H.T.
AU - Roberts, William L.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The experimental work was supported by competitive research funding from King Abdullah University of Science and Technology (KAUST), Saudi Arabia. The LES work was partly sponsored by Swedish Research Council (VR), and the Swedish Energy Agency (STEM) through the National Center for Combustion Science and Technologies (CeCOST) and Lund University Competence Center for Combustion Process (KC-FP). X. Liu and C. Gong were sponsored by China Scholarship Council (CSC).
PY - 2017/7/4
Y1 - 2017/7/4
N2 - Large eddy simulation (LES) using a transported PDF model and OH-PLIF/PIV experiments were carried out to investigate the quarl effects on the structures of swirl stabilized methane/air flames. Two different quarls were investigated, one straight cylindrical quarl and one diverging conical quarl. The experiments show that the flames are significantly different with the two quarls. With the straight cylindrical quarl a compact blue flame is observed while with the diverging conical quarl the flame appears to be long and yellow indicating a sooty flame structure. The PIV results show the formation of a stronger flow recirculation inside the diverging conical quarl than that in the straight quarl. LES results reveal further details of the flow and mixing process inside the quarl. The results show that with the diverging quarl vortex breakdown occurs much earlier towards the upstream of the quarl. As a result the fuel is convected into the air flow tube and a diffusion flame is stabilized inside the air flow tube upstream the quarl. With the straight quarl, vortex breakdown occurs at a downstream location in the quarl. The scalar dissipation rate in the shear layer of the fuel jet is high, which prevents the stabilization of a diffusion flame in the proximity of the fuel nozzle; instead, a compact partially premixed flame with two distinct heat release layers is stablized in a downstream region in the quarl, which allows for the fuel and air to mix in the quarl before combustion and a lower formation rate of soot. The results showed that the Eulerian Stochastic Fields transported PDF method can well predict the details of the swirl flame dynamics.
AB - Large eddy simulation (LES) using a transported PDF model and OH-PLIF/PIV experiments were carried out to investigate the quarl effects on the structures of swirl stabilized methane/air flames. Two different quarls were investigated, one straight cylindrical quarl and one diverging conical quarl. The experiments show that the flames are significantly different with the two quarls. With the straight cylindrical quarl a compact blue flame is observed while with the diverging conical quarl the flame appears to be long and yellow indicating a sooty flame structure. The PIV results show the formation of a stronger flow recirculation inside the diverging conical quarl than that in the straight quarl. LES results reveal further details of the flow and mixing process inside the quarl. The results show that with the diverging quarl vortex breakdown occurs much earlier towards the upstream of the quarl. As a result the fuel is convected into the air flow tube and a diffusion flame is stabilized inside the air flow tube upstream the quarl. With the straight quarl, vortex breakdown occurs at a downstream location in the quarl. The scalar dissipation rate in the shear layer of the fuel jet is high, which prevents the stabilization of a diffusion flame in the proximity of the fuel nozzle; instead, a compact partially premixed flame with two distinct heat release layers is stablized in a downstream region in the quarl, which allows for the fuel and air to mix in the quarl before combustion and a lower formation rate of soot. The results showed that the Eulerian Stochastic Fields transported PDF method can well predict the details of the swirl flame dynamics.
UR - http://hdl.handle.net/10754/625658
UR - http://www.sciencedirect.com/science/article/pii/S0016236117307986
UR - http://www.scopus.com/inward/record.url?scp=85021670527&partnerID=8YFLogxK
U2 - 10.1016/j.fuel.2017.06.092
DO - 10.1016/j.fuel.2017.06.092
M3 - Article
SN - 0016-2361
VL - 207
SP - 533
EP - 546
JO - Fuel
JF - Fuel
ER -