The convergence of theory and experiment in direct combustion generated noise

Current theories of combustion generated noise are reviewed with regard to their ability to predict the sound power output and spectral characteristics of noise generated by several flame types. New experimental information on open turbulent flames and on gas turbine combustor cans is presented. Available information on gas phase diffusion flames is reviewed. It is concluded that if some of the gross turbulence features of the flame are known and if the acoustical behavior of any flame enclosure is known, then scaling rules for behavior of the sound power output and spectral content may be quite accurately produced by theory. On the other hand, the theory is not sufficiently advanced to make absolute predictions; such predictions must await more detailed knowledge of turbulent flame structure.