Microjet Injection Strategies for Mitigating Dynamics in a Lean Premixed Swirl-Stabilized Combustor
Type
Conference PaperKAUST Grant Number
KUS-110-010-01Date
2012-06-14Online Publication Date
2012-06-14Print Publication Date
2011-01-04Permanent link to this record
http://hdl.handle.net/10754/598830
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Combustion dynamics remain a challenge in the development of low-emission, air-breathing combustors for power generation and aircraft propulsion. In this paper, we presenta parametric study on the use of microjet injectors for suppressing or mitigating the combustion dynamics that energize the thermoacoustic instability in a swirl-stabilized, premixed combustor. Microjet injectors consist of small inlet ports intended to inject flow with high momentum at relatively low mass flow rates into the flame-anchoring region. The microjets were configured to inject flow either axially, into the outer recirculation zone, or radially into the inner recirculation zone. Additionally, different injectors were tested with different relative senses of swirl (signs of angular momentum)with respect to the main flow: co-swirling, not swirling, or counter-swirling. We observed that injecting air or premixed fuel/air into the inner recirculation zone via counter-swirling radial microjets, we were able to reduce the overall sound pressure level in the combustor by over 20 dB in the lean end of the operating range. Other injector configurations were not observed to positively influence the combust or stability. Detailed PIV measurements are used to examine possible mechanisms of how the microjets impact the combustion dynamics, and the technology implications of our experiments are discussed.Sponsors
This work was undertaken with funding from the King Abdullah University of Science and Technology undergrant number KUS-110-010-01.Journal
49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Expositionae974a485f413a2113503eed53cd6c53
10.2514/6.2011-515