Acoustic oscillations in a cylindrical chamber with a hub baffle

Thomas L. Acker, Charles E. Mitchell, Jonathan D. Cody

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

The combustion-driven acoustic oscillations that occur in liquid propellant rocket engines are often similar in shape and frequency to the modes of oscillation that exist in a closed cylindrical chamber. Hub baffles can be employed to remove low-order radial modes of oscillation. In order to determine the impact of a hub baffle on low-order radial oscillations in a closed, cylindrical chamber, an analytical and computer model was developed. The governing equations of motion were solved using an eigenfunction matching technique to determine the acoustic modes of oscillation in a closed cylindrical chamber configured with a hub baffle. Results from the model show that short hub baffles significantly influence low-order radial oscillations, depressing the frequency and altering the shape of the wave. As the length of the baffle is increased, however, the radial modes of oscillation combine with successively higher longitudinal modes. The implication of this result to the overall acoustic stability of a combustion chamber is that this mode-shifting behavior may inhibit a large shift in the oscillatory frequency out of the range of frequencies sensitive to the combustion process. Furthermore, multiple solutions of the wave shape and frequency are shown to exist at some baffle lengths.

Original languageEnglish (US)
Title of host publication5th AIAA/CEAS Aeroacoustics Conference and Exhibit
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
Pages1112-1122
Number of pages11
ISBN (Print)9780000000002
StatePublished - Jan 1 1999
EventAeroacoustics Conference and Exhibit, AIAA/CEAS 1999 - Bellevue, United States
Duration: May 10 1999May 12 1999

Publication series

Name5th AIAA/CEAS Aeroacoustics Conference and Exhibit

Other

OtherAeroacoustics Conference and Exhibit, AIAA/CEAS 1999
CountryUnited States
CityBellevue
Period5/10/995/12/99

ASJC Scopus subject areas

  • Engineering(all)

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  • Cite this

    Acker, T. L., Mitchell, C. E., & Cody, J. D. (1999). Acoustic oscillations in a cylindrical chamber with a hub baffle. In 5th AIAA/CEAS Aeroacoustics Conference and Exhibit (pp. 1112-1122). [AIAA 99-1971] (5th AIAA/CEAS Aeroacoustics Conference and Exhibit). American Institute of Aeronautics and Astronautics Inc, AIAA.