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Recovery of burner acoustic source structure from far-field sound spectraA method is presented that permits the thermal-acoustic efficiency spectrum in a long turbulent burner to be recovered from the corresponding far-field sound spectrum. An acoustic source/propagation model is used based on the perturbation solution of the equations describing the unsteady one-dimensional flow of an inviscid ideal gas with a distributed heat source. The technique is applied to a long cylindrical hydrogen-flame burner operating over power levels of 4.5-22.3 kW. The results show that the thermal-acoustic efficiency at a given frequency, defined as the fraction of the total burner power converted to acoustic energy at that frequency, is rather insensitive to burner power, having a maximum value on the order of 10 to the -4th at 150 Hz and rolling off steeply with increasing frequency. Evidence is presented that acoustic agitation of the flame at low frequencies enhances the mixing of the unburned fuel and air with the hot products of combustion. The paper establishes the potential of the technique as a useful tool for characterizing the acoustic source structure in any burner, such as a gas turbine combustor, for which a reasonable acoustic propagation model can be postulated.
Document ID
19840049822
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Mahan, J. R.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Jones, J. D.
(Virginia Polytechnic Institute and State University Blacksburg, VA, United States)
Date Acquired
August 12, 2013
Publication Date
May 1, 1984
Publication Information
Publication: AIAA Journal
Volume: 22
ISSN: 0001-1452
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 83-0763
Accession Number
84A32609
Funding Number(s)
CONTRACT_GRANT: NAG3-124
Distribution Limits
Public
Copyright
Other

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