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Indirect measurement of the thermal-acoustic efficiency spectrum of a long turbulent burnerA new method is described for deducing the thermal-acoustic efficiency spectrum (defined as the fraction of combustion heat release converted to acoustic energy at a given frequency) of a long turbulent burner from the sound spectrum measured in the far field. The method, which is based on a one-dimensional model of the unsteady flow in the burner, is applied to a tubular diffusion-flame hydrogen burner whose length is large compared to its diameter. The results for thermal powers ranging from 4.5 to 22.3 kW show that the thermal-acoustic efficiency is relatively insensitive to the burner power level, decreasing from a value of around 0.0001 at 150 Hz with a slope of about 20 dB per decade. Evidence is presented indicating that acoustic agitation of the flame below 500 Hz, especially in the neighborhood of the resonant frequencies of the burner, is a significant acoustic source.
Document ID
19850036353
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Mahan, J. R.
(ONERA, Chatillon-sous-Bagneux, Hauts-de-Seine, France; Virginia Polytechnic Institute and State University Blacksburg, VA, United States)
Jones, J. D.
(NASA Langley Research Center Noise Control Branch, Hampton, VA, United States)
Blevins, L. R.
(Imperial Chemical Corporation Americas, Hopewell, VA, United States)
Cline, J. G.
(General Dynamics Corp. Fort Worth, TX, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1983
Publication Information
Issue: 4, 19
ISSN: 0379-380X
Subject Category
Acoustics
Accession Number
85A18504
Distribution Limits
Public
Copyright
Other

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