We analyze the local flame extinction and reignition of a counterflow diffusion flame perturbed by a laminar vortex ring. Local flame extinction leads to the appearance of flame edges separating the burning and extinguished regions of the distorted mixing layer. The dynamics of these edges is modeled based on previous numerical results, with heat release effects fully taken into account, which ...

Gibson scaling and related properties of flame-surface geometry in turbulent premixed combustion are demonstrated using a novel computational model, Deterministic Turbulent Mixing (DTM). In DTM, turbulent advection is represented by a sequence of maps applied to the computational domain. The structure of the mapping sequence incorporates pertinent scaling properties of the turbulent cascade. He...

The response of lean (φ 0.4) premixed hydrogen flames to maintained homogeneous isotropic turbulence is investigated using detailed numerical simulation in an idealised three-dimensional configuration over a range of Karlovitz numbers from 10 to 1562. In particular, a focus is placed on turbulence sufficiently intense that the flames can no longer be considered to be in the thin reaction burnin...

The characteristics of triple flames in a hydrogen–air mixing layer are studied using direct numerical simulation with detailed chemistry. Triple flames are initiated by imposing a temperature ignition source in the center of a scalar mixing layer of nonuniform thickness, thereby forming a pair of freely propagating triple flames. Two different fuel streams are studied: pure hydrogen and hydrog...

The lean blowout mechanisms of premixed bluff-body flames are experimentally investigated at various turbulence intensities. Turbulence levels varied using a novel generator, which combines static grid and fluidic jet impingement techniques. Three different probed to study their effects on blowout. three conditions span across the combustion regime diagram, from flamelets broken reactions. For ...

The flame in a Type Ia supernova is a conglomerate structure which, depending on density, may involve separate regions of carbon, oxygen and silicon burning, all propagating in a self-similar, subsonic front. The separation between these three burning regions increases as the density declines until eventually, below about 2 × 10 g cm, only carbon burning remains active, the other two burning ph...

Nonpremixed turbulent reacting flows are intrinsically difficult to model due to the strong coupling between turbulent motions and reaction. The large amount of heat released by a typical hydrocarbon flame leads to significant modifications of the thermodynamic variables and the molecular transport coefficients and thus alters the fluid dynamics [1],[4]. Additionally, in nonpremixed combustion,...