scholarly journals Vectorial structure of the near-wall premixed flame

2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Peipei Zhao ◽  
Lipo Wang ◽  
Nilanjan Chakraborty
Keyword(s):  
Premixed Flame ◽  
Vectorial Structure ◽  
Near Wall

scholarly journals Direct numerical simulation of premixed flame boundary layer flashback in turbulent channel flow

2012 ◽  
Vol 709 ◽  
pp. 516-542 ◽  
Author(s):  
A. Gruber ◽  
J. H. Chen ◽  
D. Valiev ◽  
C. K. Law
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Channel Flow ◽  
Hydrodynamic Instability ◽  
Leading Edge ◽  
Turbulent Channel Flow ◽  
Turbulent Boundary Layers ◽  
Premixed Flame ◽  
Flame Sheet ◽  
Near Wall

AbstractDirect numerical simulations are performed to investigate the transient upstream propagation (flashback) of premixed hydrogen–air flames in the boundary layer of a fully developed turbulent channel flow. Results show that the well-known near-wall velocity fluctuations pattern found in turbulent boundary layers triggers wrinkling of the initially flat flame sheet as it starts propagating against the main flow direction, and that the structure of the characteristic streaks of the turbulent boundary layer ultimately has an important impact on the resulting flame shape and on its propagation mechanism. It is observed that the leading edges of the upstream-propagating premixed flame are always located in the near-wall region of the channel and assume the shape of several smooth, curved bulges propagating upstream side by side in the spanwise direction and convex towards the reactant side of the flame. These leading-edge flame bulges are separated by thin regions of spiky flame cusps pointing towards the product side at the trailing edges of the flame. Analysis of the instantaneous velocity fields clearly reveals the existence, on the reactant side of the flame sheet, of backflow pockets that extend well above the wall-quenching distance. There is a strong correspondence between each of the backflow pockets and a leading edge convex flame bulge. Likewise, high-speed streaks of fast flowing fluid are found to be always colocated with the spiky flame cusps pointing towards the product side of the flame. It is suggested that the origin of the formation of the backflow pockets, along with the subsequent mutual feedback mechanism, is due to the interaction of the approaching streaky turbulent flow pattern with the Darrieus–Landau hydrodynamic instability and pressure fluctuations triggered by the flame sheet. Moreover, the presence of the backflow pockets, coupled with the associated hydrodynamic instability and pressure–flow field interaction, greatly facilitate flame propagation in turbulent boundary layers and ultimately results in high flashback velocities that increase proportionately with pressure.

Influence of Surface Reaction on Near-Wall Premixed Flame Behavior

2018 ◽  
Vol 2018 (0) ◽  
pp. 0010
Author(s):  
Kosuke Narukawa ◽  
Yuki Minamoto ◽  
Masayasu Shimura ◽  
Mamoru Tanahashi
Keyword(s):  
Surface Reaction ◽  
Premixed Flame ◽  
Flame Behavior ◽  
Near Wall

Near-Wall Unsteady Premixed Flame Propagation in S.I. Engines

1995 ◽  
Author(s):  
Tobias Steiner ◽  
Konstantinos Boulouchos
Keyword(s):  
Flame Propagation ◽  
Premixed Flame ◽  
Near Wall

NEAR-WALL CHARACTERISTICS OF AN IMPINGING GASOLINE SPRAY AT INCREASED AMBIENT PRESSURE AND WALL TEMPERATURE

2009 ◽  
Vol 19 (11) ◽  
pp. 997-1012 ◽  
Author(s):  
Jochen Stratmann ◽  
D. Martin ◽  
P. Unterlechner ◽  
R. Kneer
Keyword(s):  
Wall Temperature ◽  
Ambient Pressure ◽  
Near Wall

Nonisothermal Mixing of a Near-Wall Gas-Liquid Jet with a Flow in a Tube

2001 ◽  
Vol 32 (4-6) ◽  
pp. 7
Author(s):  
Viktor I. Terekhov ◽  
K. A. Sharov ◽  
N. E. Shishkin ◽  
V. P. Lebedev
Keyword(s):  
Liquid Jet ◽  
Near Wall

A NUMERICAL INVESTIGATION OF NEAR WALL HEAT TRANSFER

1994 ◽  
Author(s):  
P.J. Stuttaford ◽  
S. Anghaie ◽  
Wei Shyy
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Wall Heat Transfer ◽  
Near Wall

Modeling Spark Ignition and Partially Premixed Flame Propagation in DISI Engines

2002 ◽  
Author(s):  
Gunnar Dr. Stiesch ◽  
Sven Pagel ◽  
Gunter P. Merker
Keyword(s):  
Flame Propagation ◽  
Spark Ignition ◽  
Premixed Flame ◽  
Partially Premixed ◽  
Partially Premixed Flame
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