Nonlinear effects in the extraction of laminar flame speeds from expanding spherical flames

Journal Article · Tue Sep 15 00:00:00 EDT 2009 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2009.04.004· OSTI ID:21223037

Kelley, A P; Law, C K ^[1]

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1. Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

Various factors affecting the determination of laminar flames speeds from outwardly propagating spherical flames in a constant-pressure combustion chamber were considered, with emphasis on the nonlinear variation of the stretched flame speed to the flame stretch rate, and the associated need to nonlinearly extrapolate the stretched flame speed to yield an accurate determination of the laminar flame speed and Markstein length. Experiments were conducted for lean and rich n-butane/air flames at 1atm initial pressure, demonstrating the complex and nonlinear nature of the dynamics of flame evolution, and the strong influences of the ignition transient and chamber confinement during the initial and final periods of the flame propagation, respectively. These experimental data were analyzed using the nonlinear relation between the stretched flame speed and stretch rate, yielding laminar flame speeds that agree well with data determined from alternate flame configurations. It is further suggested that the fidelity in the extraction of the laminar flame speed from expanding spherical flames can be facilitated by using small ignition energy and a large combustion chamber. (author)

• OSTI ID: 21223037
• Journal Information: Combustion and Flame, Vol. 156, Issue 9; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
LAMINAR FLAMES
SPHERICAL CONFIGURATION
VELOCITY
BUTANE
NONLINEAR PROBLEMS
EXPERIMENTAL DATA
LENGTH
AIR
EXTRAPOLATION
COMBUSTION CHAMBERS
IGNITION
FLAME PROPAGATION
CONFINEMENT
TIME DEPENDENCE
TRANSIENTS
VARIATIONS
YIELDS
ATMOSPHERIC PRESSURE
Propagating spherical flames
Markstein length