Characterization of acoustic effects on flame structures by beam deflection technique
This work shows that the acoustic effects are the causes of the small amplitude flame wrinkling and movements seen in all the different gravitational conditions. The comparison between the acoustic velocity and beam deflection spectra for the two conditions studied (glass beads and fiber glass) demonstrates clearly this flame/acoustic coupling. This acoustic study shows that the burner behaves like a Helmholtz resonator. The estimated resonance frequency corresponds well to the experimental measurements. The fiber glass damps the level of the resonance frequency and the flame motion. The changes shown in normalized beam deflection spectra give further support of this damping. This work demonstrates that the acoustics has a direct influence on flame structure in the laminar case and the preliminary results in turbulent case also show a strong coupling. The nature of this flame/acoustic coupling are still not well understood. Further investigation should include determining the frequency limits and the sensitivity of the flame to acoustic perturbations.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States)
- Sponsoring Organization:
- National Aeronautics and Space Administration, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 10104729
- Report Number(s):
- LBL--34700; CONF-931076--3; ON: DE94003240; CNN: C-32000-R
- Country of Publication:
- United States
- Language:
- English
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