Results 261 to 270 of about 82,402 (301)

On Spinning Propagation of Cellular Flames

Combustion Science and Technology, 1990
Abstract The appearance of time-dependent cellular structures in premixed flame propagation is known to occur in a parameter regime usually associated with the onset of steady cellular flame formation. We consider this phenomenon in the context of a model for downward flame propagation in vertical channels.
STEPHEN B. MARGOLIS, GREGORY I. SIVASHINSKY   +1 more
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The characteristics of four ratcheting states in cellular flames

Chaos: An Interdisciplinary Journal of Nonlinear Science, 2009
A premixed flat flame on a circular porous plug burner can form patterns of one or two concentric rings of cells in which brighter, hotter regions are separated by darker, cooler cusps and folds. Dynamic states are found at parameter values that are interleaved between those of the ordered states.
M, Gorman, M, el-Hamdi, B, Pearson
openaire   +2 more sources

Extinction and cellular instability of premixed tubular flames

Proceedings of the Combustion Institute, 2008
Extinction and cellular instabilities are investigated in premixed tubular flames. A tubular burner has recently been designed and constructed to be capable of operating under a wide range of conditions that allow more accurate and detailed study of tubular premixed and non-premixed flames.
Yu Wang, Shengteng Hu, Robert Pitz
openaire   +1 more source

Modal decomposition of hopping states in cellular flames

Chaos: An Interdisciplinary Journal of Nonlinear Science, 1999
We use Karhunen–Loeve (KL) decomposition of video images from an experiment to analyze a spatiotemporal dynamic state, unique to cellular flames, referred to as a “hopping state.” Ordered states of cellular flames on a circular burner consist of one or two concentric rings of luminous cells.
Palacios, Antonio, Gorman, Michael, Gunaratne, Gemunu H.   +2 more
openaire   +2 more sources

Numerical Simulation of Cellular Flame Propagation in Narrow Gaps

Mathematical Models and Computer Simulations, 2022
Summary: A computational model for combustion of premixed gases in narrow gaps between parallel plates is presented. The model is based on the numerical solution of conservation equations for multicomponent reacting gas flow in the small Mach number approximation. Detailed kinetic mechanism is used to describe combustion reactions.
Borisov, V. E., Yakush, S. E., Sysoeva, E. Ya.   +2 more
openaire   +2 more sources

The cellular nature of hydrodynamic flame instability

Physica D: Nonlinear Phenomena, 1990
Abstract The nonlinear evolution of a weakly perturbed planar flame under the influence of the Landau-Darrieus instability is studied numerically. It is shown that in sufficiently small-scale systems spontaneous instability appears in the guise of a cusp-shape flame.
Gutman, S., Sivashinsky, G. I.
openaire   +1 more source

On transition to cellularity in expanding spherical flames

Journal of Fluid Mechanics, 2007
The instant of transition to cellularity of centrally ignited, outwardly propagating spherical flames in a reactive environment of fuelx–oxidizer mixture, at atmospheric and elevated pressures, was experimentally determined using high-speed schlieren imaging and subsequently interpreted on the basis of hydrodynamic and diffusional–thermal instabilities.
G. JOMAAS, C. K. LAW, J. K. BECHTOLD
openaire   +1 more source

On curved cellular flames

2008
Laminar premixed flames exhibit cellular instabilities for sufficiently small Lewis-numbers. In the present article we study a modified Kuramoto-Sivashinsky-equation describing curved, cellular flames near the instability threshold. Pattern formation is strongly influenced by the sign of flame curvature.
openaire   +1 more source

A theoretical derivation of cellular structures of flames

Zeitschrift f�r Physik B Condensed Matter, 1985
Using an equation for the formation of flame fronts derived by Sivashinsky and augmented by an additional term describing buoyancy effects we present an analytical treatment of the formation of cellular structures of flames formed by plane burners. In particular we find rectangular and square patterns.
B. Schnaufer, H. Haken
openaire   +1 more source

Self-fragmentation of nonadiabatic cellular flames

Combustion and Flame, 1997
A simple thermal-diffusive model for premixed flames with radiative heat losses is studied numerically. In accordance with previous analytical predictions, it is shown that cellular flames occurring in low Lewis number premixtures can propagate with heat-loss rates greater than the maximum that extinguishes the planar flame.
L. Kagan, G. Sivashinsky
openaire   +1 more source