Smolder waves, smolder spots, and the genesis of tribrachial structures in smolder combustion

摘要

We examine the evolution of reverse smolder waves with edges, motivated by the existing literature on edge-flames. An advancing smolder edge proves to be of little interest, and a well-defined invariant structure does not emerge following initial transients. A retreating smolder edge also lacks invariant structure, but retreats at a reasonably well-defined speed and can lead to novel structures and novel evolutions. Thus, a transient propagating smolder spot can be generated; and a tribrachial structure evolves from this spot with a tail that has the form of a forward smolder wave, and two leading branches, fuel-lean and fuel-rich reverse smolder waves. High temperatures and high reaction rates accompany these evolutions, and it is noted that this could lead to flaming (gas-phase) combustion.