Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2014
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| Online Access: | http://hdl.handle.net/1721.1/92158 |
| _version_ | 1826202263761190912 |
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| author | Hong, Seung Hyuck |
| author2 | Ahmed F. Ghoniem. |
| author_facet | Ahmed F. Ghoniem. Hong, Seung Hyuck |
| author_sort | Hong, Seung Hyuck |
| collection | MIT |
| description | Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. |
| first_indexed | 2024-09-23T12:04:46Z |
| format | Thesis |
| id | mit-1721.1/92158 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T12:04:46Z |
| publishDate | 2014 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/921582019-04-11T10:21:33Z Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure Hong, Seung Hyuck Ahmed F. Ghoniem. Massachusetts Institute of Technology. Department of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering. Mechanical Engineering. Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. Cataloged from PDF version of thesis. Includes bibliographical references (pages 207-216). Combustion dynamics are critical to the development of high-efficiency, low-emission and fuel-flexible combustion systems used for propulsion and power generation. Predicting the onset of dynamics remains a challenge because of the complex interactions among several multi-scale phenomena, including turbulence, kinetics and acoustics, and their strong dependence on the operating conditions and fuel properties. In this thesis, a series of experiments were conducted in a laboratory-scale combustor, burning lean premixed propane/hydrogen/air mixtures over a range of equivalence ratio, fuel composition and inlet temperature. Dynamic pressure and flame chemiluminescence measurements are used to determine macro-scale characteristics such as the frequency, limit cycle amplitude and dynamic flame shape. High-speed, high-resolution particle image velocimetry (PIV) is used to quantify the micro-scale structure of the flow, while planar laser-induced fluorescence (PLIF) of OH radical is used to investigate the flame microstructure. Results demonstrate that combustion dynamics in wake-stabilized flames can be characterized using a single non-dimensional parameter that collapses many response measures over a range of operating conditions and fuel composition, including the critical wake length at which dynamics is first observed, the critical phase at which transition among dynamic modes is encountered, and the limit cycle amplitude, emphasizing the role of the physics and chemistry of the flame processes in driving the overall system dynamics and encapsulating the governing mechanisms. The proposed parameter is based on the normalized strained flame consumption speed, which encapsulates the flow-combustion interactions at the flame scale. PIV data reveal significant changes in the recirculation zone structure depending on the equivalence ratio and the fuel composition, demonstrating the impact of chemical kinetics on the flow. These changes are shown to correlate strongly with the stability characteristics, i.e., blow-off and flashback limits as well as the onset of the thermoacoustic instabilities, highlighting a critical role of the recirculation zone in flame stabilization. An expression for the critical phase at which dynamic mode transition occurs is derived based on the linear acoustic energy balance. It is shown that the critical phase is also a function of the same non-dimensional parameter, suggesting that it represents the state within a dynamic mode as well. Results show that the normalized phase correlates with the upper- and lower-boundary of a dynamic mode, thus being a necessary and sufficient condition for dynamics. The results provide a metric for quantifying the instability margins of fuel-flexible combustors operating over a wide range of conditions. Analysis of PIV and OH-LIF data suggests that heat transfer near the flame-holder may play an important role in determining the stability characteristics. The impact of heat transfer on the onset of dynamics is experimentally investigated using different flame-holders. Results demonstrate the effectiveness of using heat-insulating materials as a passive control strategy to prevent or significantly delay the onset of the instabilities. by Seung Hyuck Hong. Ph. D. 2014-12-08T18:53:10Z 2014-12-08T18:53:10Z 2014 2014 Thesis http://hdl.handle.net/1721.1/92158 897122396 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 216 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Hong, Seung Hyuck Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure |
| title | Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure |
| title_full | Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure |
| title_fullStr | Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure |
| title_full_unstemmed | Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure |
| title_short | Towards predicting dynamics in turbulent premixed combustion using PIV-PLIF measurements of flow-flame microstructure |
| title_sort | towards predicting dynamics in turbulent premixed combustion using piv plif measurements of flow flame microstructure |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/92158 |
| work_keys_str_mv | AT hongseunghyuck towardspredictingdynamicsinturbulentpremixedcombustionusingpivplifmeasurementsofflowflamemicrostructure |