Vorticity isotropy in high Karlovitz number premixed flames

Low vorticity and small gas expansion in premixed flames

Simulation of premixed turbulent flames

1. Introduction Premixed turbulent flames are of increasing practical importance and remain a significant research challenge in the combustion community. These flames have the potential to operate cleanly and efficiently over a broad range of fuels, and therefore to represent a key element in the implementation of low-emissions burners for a variety of industrial applications. However, it is di...

Reaction-Sheet Jump Conditions in Premixed Flames

The fundamental differences between the leading-order jump conditions, often assumed at a flame sheet in combustion theory, and the actual effect of a chemical reaction that satisfies Arrhenius kinetics with a finite activation temperature, need to be understood. These differences are “higher order” in terms of a large activation temperature analysis. However, they do provide a quantitative est...

Gravity Effects Observed in Partially Premixed Flames

INTRODUCTION Partially premixed flames (PPFs) contain a rich premixed fuel–air mixture in a pocket or stream, and, for complete combustion to occur, they require the transport of oxidizer from an appropriately oxidizer–rich (or fuel–lean) mixture that is present in another pocket or stream. Partial oxidation reactions occur in fuel–rich portions of the mixture and any remaining unburned fuel an...

Acoustic Detection of Blowout in Premixed Flames

Work to develop a practical, fast diagnostic technique to monitor the proximity of a combustor to blowout using measurements of the flame’s acoustic signature is described. The feasibility of this approach was demonstrated on three combustors with different flame holding mechanisms that are used in most practical combustion devices: pilot, swirl, and bluff-body stabilized flames. Extensive high...