Acoustic Instability in Premixed Flames

Abstract

This short paper presents an experimental description of the acoustic instability of a premixed flame front propagating in a tube. Four distinct types of behaviour are identified. Firstly a regime of acoustic stability in which the flame is cellular and non vibrating. Secondly a regime of primary acoustic instability in which the flame is quasi planar. Thirdly a regime of secondary acoustic instability, in which the oscillations can reach very high amplitudes, and where the flame front develops pulsating cellular structures. This latter regime breaks down into an incoherent auto-turbulent regime at sufficiently high acoustic amplitudes.

Key words:

• Laminar premixed flames
• acoustic instability
• experiments