Sk. Scott et al., MODELING STUDIES OF SPIRAL WAVES AND TARGET PATTERNS IN PREMIXED FLAMES, Journal of the Chemical Society. Faraday transactions, 93(9), 1997, pp. 1733-1739
Citations number
49
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
Spiral waves and target patterns have recently been observed experimen
tally in freely propagating and burner-stabilised flames, typically in
systems close to the lean flammability limit and for which the Lewis
number (Le, the ratio of thermal to mass diffusivity) exceeds unity. A
n interpretation of these observations based on a simple two-reaction
model (the Sal'nikov model) is developed here in terms of the excitabi
lity of the system rather than by ascribing any special role to the Le
wis number. The conditions for excitability are derived in terms of th
e various experimental parameters (reaction rate coefficients, exother
micity, initial concentrations, heat transfer coefficient, etc.) and t
his information is then used to direct a numerical search for wave beh
aviour in the reaction-diffusion equations. The conditions for wave pr
opagation are then established in terms of the experimental parameters
and examples of target and spiral waves computed. Waves are shown to
exist for a wide range of Lewis number, including Le < 1, but it is al
so observed that high values of Le appear to increase the range of the
conditions over which waves can be supported.