Observables for the Response of Laminar Flames to Acoustic Disturbance

The detection of the response of flames to acoustic disturbances is of importance for both laboratory situations and practical equipment. For the main observables of interest, heat release and velocity, the detection is quite difficult and too costly to implement in real life aplications. This paper presents an experimental and numerical study into a number of observables that show instationary effects when a flame is acoustically disturbed. The flame configuration is very basic, consisting of a flat laminar premixed methane-air flame, stabilized on a porous ceramic material. The observables of interest are velocity, heat release, chemoluminescence of CH and OH, and temperature. The conclusions are that velocity and chemoluminescence are in principle excellent indicators for the flame’s response, but for the given specific setup there is a too large discrepancy between the experimental and numerical results with regard to chemoluminescence. Temperature fluctuations are significant but are, due to the strong position dependence, not very suitable as an observable.