The downstream boundary effects on the spectral characteristics of the combustor swirling flowfield
Abstract
The spectral characteristics and flow structural response of the combustor swirling flowfield subject to downstream boundary disturbance are investigated. Two types of disturbance are imposed at the downstream boundary. They are downstream contraction and asymmetric disturbance. Three natural frequencies are noted in different regions of the swirling flowfield. Downstream contraction usually causes compression of the central recirculation zone into two side-lobes, increases the PVC's (precession vortex core) fundamental frequency and decreases its oscillation energy. For asymmetric disturbance, such as the passing of the turbine blades, the PVC's fundamental frequency is not altered below certain critical disturbance amplitude and the precession energy drops tremendously. In addition, the precession energy is enlarged as the excitation frequency approaches the PVC's fundamental frequency.
- Publication:
-
26th AIAA Aerospace Sciences Meeting
- Pub Date:
- January 1988
- Bibcode:
- 1988aiaa.meetQW...C
- Keywords:
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- Boundary Layer Stability;
- Combustion Chambers;
- Flow Distribution;
- Flow Measurement;
- Swirling;
- Vortex Breakdown;
- Resonant Frequencies;
- Test Facilities;
- Fluid Mechanics and Heat Transfer