TY - JOUR
T1 - On the determination of laminar flame speeds from stretched flames
AU - Wu, C. K.
AU - Law, C. K.
N1 - Funding Information:
This work was supported by NASA-Lewis under Grant NAG3-361 and the Department of Energy under Contract DE-AC02-84ER13173. We thank Professors S. H. Chung, K. Miyasaka, and R. S. Tankin for technical discussions and assistance with the experimentation. The work was performed while, the first author was on sabbatical leave at North-western-University.
PY - 1985
Y1 - 1985
N2 - The effects of stretch on the determination of the laminar flame speed are experimentally studied by using the positively-stretched stagnation flame and negatively-stretched bunsen flame, and by using lean and rich mixtures of methane, propane, butane, and hydrogen with air whose effective Lewis numbers are either greater or less than unity. Results demonstrate that flame speed determination can be influenced by stretch through two factors: (1) Preferential diffusion which tends to increase or decrease the flame temperature and burning rate depending on the effective Lewis number, and (2) Flow divergence which causes the flame speed to assume higher values when evaluated at the upstream boundary of the preheat zone instead of the reaction zone. Recent data on flame speed including the present ones are then examined from the unified viewpoint of flame stretch, leading to satisfactory resolution of the discrepancies between them. The present study also proposes a methodology of determining the laminar flame speeds by using the stagnation flame and linearly extrapolating the data to zero stretch rate.
AB - The effects of stretch on the determination of the laminar flame speed are experimentally studied by using the positively-stretched stagnation flame and negatively-stretched bunsen flame, and by using lean and rich mixtures of methane, propane, butane, and hydrogen with air whose effective Lewis numbers are either greater or less than unity. Results demonstrate that flame speed determination can be influenced by stretch through two factors: (1) Preferential diffusion which tends to increase or decrease the flame temperature and burning rate depending on the effective Lewis number, and (2) Flow divergence which causes the flame speed to assume higher values when evaluated at the upstream boundary of the preheat zone instead of the reaction zone. Recent data on flame speed including the present ones are then examined from the unified viewpoint of flame stretch, leading to satisfactory resolution of the discrepancies between them. The present study also proposes a methodology of determining the laminar flame speeds by using the stagnation flame and linearly extrapolating the data to zero stretch rate.
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U2 - 10.1016/S0082-0784(85)80693-7
DO - 10.1016/S0082-0784(85)80693-7
M3 - Article
AN - SCOPUS:58149372612
SN - 0082-0784
VL - 20
SP - 1941
EP - 1949
JO - Symposium (International) on Combustion
JF - Symposium (International) on Combustion
IS - 1
ER -