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naca-tn-3983

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National Advisory Committee for Aeronautics, Technical Notes - Effect of Standing Transverse Acoustic Oscillations on Fuel Oxidant Mixing in Cylindrical Combustion Chambers

The effect of acoustic oscillations on fuel—oxidant mixing is ana-
lyzed for acoustic conditions commonly found in screeching and screaming
combustors. Transverse acoustic fields in cylindrical ducts are described
in terms of pressure fluctuation, particle velocity, and oscillation
frequency. The effect of such acoustic fields on the fuel-oxidant mixing
downstream from point sources of injection is treated theoretically to
obtain expressions relating the fuelroxidant ratio to the parameters of
the stream and the acoustic field. Numerical solutions of these relations
are made to illustrate the effect of sound-pressure level, oscillation
frequency, stream velocity, and turbulence level. The results of this
analysis show that, for moderate screech or scream levels, the fuel—
oxidant mixing wake is given a transverse oscillatory motion of consider-
able magnitude and that the fuel-oxidant ratio undergoes large cyclic
fluctuations which are in phase with the pressure fluctuations of the
acoustic field. A number of possible mechanisms contributing to screech
and scream in various combustor configurations are proposed, and methods
for their control are suggested.

The effect of acoustic fields on vapor mixing is of interest to the
combustion problem in screeching or screaming combustors. If the acoustic
oscillations change the fuel-air or fuel-oxidant ratio, the combustion
process will'be directly affected. To illustrate the effect of acoustic
oscillations, an analysis has been made of vapor mixing in cylindrical
ducts under conditions usually found in screeching ramjets and after-
burners and in screaming rockets.

Acoustic oscillations in cylindrical chambers have three general
modes: longitudinal, radial, and tangential, as illustrated.by*the
following pressure fluctuation diagrams showing pressure fluctuation
contours at an instant in time.

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naca-tn-3983

  • Version
  • 34 Downloads
  • 1.99 MB File Size
  • 1 File Count
  • January 29, 2017 Create Date
  • January 29, 2017 Last Updated
Scroll for Details

National Advisory Committee for Aeronautics, Technical Notes - Effect of Standing Transverse Acoustic Oscillations on Fuel Oxidant Mixing in Cylindrical Combustion Chambers

The effect of acoustic oscillations on fuel—oxidant mixing is ana-
lyzed for acoustic conditions commonly found in screeching and screaming
combustors. Transverse acoustic fields in cylindrical ducts are described
in terms of pressure fluctuation, particle velocity, and oscillation
frequency. The effect of such acoustic fields on the fuel-oxidant mixing
downstream from point sources of injection is treated theoretically to
obtain expressions relating the fuelroxidant ratio to the parameters of
the stream and the acoustic field. Numerical solutions of these relations
are made to illustrate the effect of sound-pressure level, oscillation
frequency, stream velocity, and turbulence level. The results of this
analysis show that, for moderate screech or scream levels, the fuel—
oxidant mixing wake is given a transverse oscillatory motion of consider-
able magnitude and that the fuel-oxidant ratio undergoes large cyclic
fluctuations which are in phase with the pressure fluctuations of the
acoustic field. A number of possible mechanisms contributing to screech
and scream in various combustor configurations are proposed, and methods
for their control are suggested.

The effect of acoustic fields on vapor mixing is of interest to the
combustion problem in screeching or screaming combustors. If the acoustic
oscillations change the fuel-air or fuel-oxidant ratio, the combustion
process will'be directly affected. To illustrate the effect of acoustic
oscillations, an analysis has been made of vapor mixing in cylindrical
ducts under conditions usually found in screeching ramjets and after-
burners and in screaming rockets.

Acoustic oscillations in cylindrical chambers have three general
modes: longitudinal, radial, and tangential, as illustrated.by*the
following pressure fluctuation diagrams showing pressure fluctuation
contours at an instant in time.

FileAction
naca-tn-3983 Effect of Standing Transverse Acoustic Oscillations on Fuel Oxidant Mixing in Cylindrical Combustion Chambers.pdfDownload 
17,005 Documents in our Technical Library
2449841 Total Downloads

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Newest Additions

NASA-RP-1060 Subsonic Aircraft: Evolution and the Matching of Size to Performance
NASA-RP-1060 Subsonic Aircraft: Evolution and the Matching of Size to Performance
AA-CP-20212-001
AA-CP-20212-001
ADPO10769 Occurrence of Corrosion in Airframes
The purpose of this lecture is to provide an overview ...
MIL-STD-1759 Rivets and Rivet Type Fasteners Preferred for Design
The purpose of this book form standard is to provide ...
MIL-STD-810G Environmental Engineering Considerations and Laboratory Tests
This standard contains materiel acquisition program planning and engineering direction ...