A REVIEW OF RIJKE TUBES, RIJKE BURNERS AND RELATED DEVICES

Thermoacoustic devices related to the Rijke tube are reviewed. Most modem thermoacoustic devices use as a heat source a heated wire or ribbon or a premixed gas flame anchored to a metal gauze, metal tube matrix or porous ceramic frit. Numerous experiments have confirmed that combustion-driven oscillations in tube devices are 'Rijke tube' or 'organ pipe' oscillations, i.e. frequencies are the same as those in a Rijke tube or organ pipe of the same length and with the same gas temperature distribution. Experiments have also established the validity of Rayleigh's stability criterion for the development of heat-driven acoustic oscillations. Modem mathematical analyses of acoustic oscillations in Rijke-type devices begin with a common basis: equations for mass, momentum and energy conservation. Almost all analyses assume constant hot section temperature. The main difference between analyses is the manner in which the oscillating response of the heat source is modeled. Frequency of oscillation is governed primarily by the acoustic speed of gases in a chamber. Thus, the flame or heater response model used does not significantly effect frequency predictions. However, the flame or heater response model can have a dramatic effect on predicted growth rates. Since flame models influence predicted response of Rijke burners, some work with vibrating flames is also reviewed. Flame response models vary widely, from simple phenomenological models to sophisticated models based on large activation energy asymptotic theory.