SIGN-IN

Publication: Effect of discreteness on heterogeneous flames: Propagation limits in regular and random particle arrays

All || By Area || By Year

Title Effect of discreteness on heterogeneous flames: Propagation limits in regular and random particle arrays
Authors/Editors* Tang, F. D., A.J. Higgins, S. Gorosin
Where published* Combustion Theory and Modelling
How published* Journal
Year* 2009
Volume 13
Number 2
Pages 319-341
Publisher Taylor and Francis
Keywords
Link heterogeneous combustion
Abstract
In a system with discrete heat sources distributed in an inert, heat conducting medium, there exists two asymptotic regimes of flame propagation. When the flame thickness is much greater than the inter-particle spacing, the system approximates a homogeneous medium and the flame can be modeled as a continuum. In the other extreme, when the flame is very thin due to rapid reaction of particles, the heterogeneous flame can no longer be treated as a continuum since discrete effects become dominant. The effects of discreteness are characterized by a strong dependence on the spatial distribution of the sources. The present work investigates the effects of discreteness on flame propagation and demonstrates that these effects result in a propagation limit in the absence of losses. For a system of regularly spaced particles, this limit can be found analytically for one-, two-, and three-dimensional systems, although the flame exhibits a complex dynamic of bifurcations as it approaches this limit. Propagation of a flame beyond this limit is only possible through concentration fluctuations in a system with randomly distributed particles. Two-dimensional numerical simulations with randomly distributed particles show a strong dependence of the propagation limit on the size of the computational domain. A consequence of the random particle distribution is that the flammability limit can only be defined as a probabilistic outcome of the flame propagation simulations.
Go to Nuclear, Aerospace, Biomedical Engineering
Back to page 33 of list