Acoustic effects during the combustion of gaseous fuels in a bubbling fluidized bed

Acoustic effects accompany the combustion of gaseous fuels in bubbling flui dized beds of inert materials. In an exploratory study of this effect, usin g a laboratory-size fluidized bed in which a mixture of propane and butane was burned, the bed's temperature was monitored continuously and the acoust ic effects were recorded. The temperature ranges over which combustion was "noisy" and "quiet" were identified; the acoustic signals were shown to fal l into a number of characteristic patterns, which can yield information abo ut the character of the combustion process, in relation to "mini-explosions " in bubbles of the combustible mixture rising through the bed, their inten sity and frequency. The results could be used to develop a new method of co ntrolling the operation of fluidized beds burning a gaseous fuel. (C) 1999 by The Combustion Institute.