Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2011
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| Online Access: | http://hdl.handle.net/1721.1/67803 |
| _version_ | 1826196753822515200 |
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| author | Shroll, Andrew Philip |
| author2 | Ahmed F. Ghoniem. |
| author_facet | Ahmed F. Ghoniem. Shroll, Andrew Philip |
| author_sort | Shroll, Andrew Philip |
| collection | MIT |
| description | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011. |
| first_indexed | 2024-09-23T10:37:30Z |
| format | Thesis |
| id | mit-1721.1/67803 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T10:37:30Z |
| publishDate | 2011 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/678032019-04-12T09:52:38Z Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion Shroll, Andrew Philip Ahmed F. Ghoniem. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Mechanical Engineering. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011. Cataloged from PDF version of thesis. Includes bibliographical references (p. 83-86). Oxy-fuel combustion is a promising technology to implement carbon capture and sequestration for energy conversion to electricity in power plants that burn fossil fuels. In oxy-fuel combustion, air separation is used to burn fuel in oxygen to easily obtain a pure stream of carbon dioxide from the products of combustion. A diluent, typically carbon dioxide, is recycled from the exhaust to mitigate temperature. This substitution of carbon dioxide with the nitrogen in air alters the thermodynamics, transport properties, and relative importance of chemical pathways of the reacting mixture, impacting the flame temperature and stability of the combustion process. In this thesis, methane oxy-combustion flames are studied for relevance to natural gas. First, a numerical 1-D strained flame shows significantly reduced consumption speeds for oxy-combustion compared to air combustion at the same adiabatic flame temperature. Competition for the H radical from the presence of carbon dioxide causes high CO emissions. Elevated strain rates also cause incomplete combustion in oxy-combustion, demonstrated by the effect of Lewis number with a value greater than one for flame temperatures under 1900 K. Most of this work focuses on experimental results from premixed flames in a 50 kW axi-symmetric swirl-stabilized combustor. Combustion instabilities, upon which much effort is expended to avoid in gas turbines with low pollutant emissions, are described as a baseline for the given combustor geometry using overall sound pressure level maps and chemiluminescence images of 1/4, 3/4, and 5/4 wave mode limit cycles. These oxy-combustion results are compared to conventional air combustion, and the collapse of mode transitions with temperature for a given Reynolds number is found. Hysteresis effects in mode transition are important and similar for air and oxy-combustion. Blowoff trends are also analyzed. While oxy-combustion flames blow off at a higher temperature for a given Reynolds number due to weaker flames, there is an unexpected negative slope in blowoff velocity vs temperature for both air and oxy-combustion. The blowoff data are shown to collapse due to blowoff velocity being inversely proportional to the molar heat capacities of the burned gas mixtures at a given power. Finally, particle image velocimetry results are discussed to relate flow structures to corresponding flame structures. by Andrew Philip Shroll. S.M. 2011-12-19T18:53:19Z 2011-12-19T18:53:19Z 2011 2011 Thesis http://hdl.handle.net/1721.1/67803 767830196 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 86 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Shroll, Andrew Philip Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion |
| title | Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion |
| title_full | Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion |
| title_fullStr | Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion |
| title_full_unstemmed | Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion |
| title_short | Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion |
| title_sort | dynamic stability blowoff and flame characteristics of oxy fuel combustion |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/67803 |
| work_keys_str_mv | AT shrollandrewphilip dynamicstabilityblowoffandflamecharacteristicsofoxyfuelcombustion |