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Investigation of Plasma-Assisted Combustion in Swirling Flow Conditions
Investigation of Plasma-Assisted Combustion in Swirling Flow Conditions
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260209102912
- ISBN
- 9798265403889
- DDC
- 621.165
- 저자명
- Choe, Jinhoon.
- 서명/저자
- Investigation of Plasma-Assisted Combustion in Swirling Flow Conditions
- 발행사항
- [Sl] : Georgia Institute of Technology, 2023
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2023
- 형태사항
- 159 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 87-05, Section: B.
- 주기사항
- Advisor: Sun, Wenting.
- 학위논문주기
- Thesis (Ph.D.)--Georgia Institute of Technology, 2023.
- 초록/해제
- 요약This study presents the effect of a nanosecond pulsed plasma on premixed methane/air and ammonia/air flames in a model gas turbine dump combustor with an annular swirling flow. A hysteresis phenomenon on blowoff is observed in the study of methane/air flames. Therefore, the lean blowoff limit is not uniquely defined. This hysteresis phenomenon depends on the initial value of the equivalence ratio at which the flame is ignited and the air velocity. Different methane/air flame morphologies are also observed depending on the equivalence ratio and the region where the flame is stabilized. If a nanosecond pulsed plasma is applied at the combustor nozzle exit, a stable inner shear layer flame is always observed. The lean blowoff limit is significantly extended, and the hysteresis phenomenon disappears with plasma activation. This indicates that plasma provides an additional mechanism for flame stabilization. It is found that plasma activation increases NOx concentration and decreases CO concentration through emission analysis.Ammonia (NH3) is a carbon-free fuel with high hydrogen content. However, the application of ammonia/air combustion has two significant challenges: high NOx emission and poor flame stability. This study also presents the effects of the nanosecond pulsed plasma on ammonia/air flames to overcome these two challenges. Both lean blowoff limits and NOx emission are investigated in a premixed swirl burner with nanosecond pulsed plasma. With plasma activation, the lean blowoff limits of ammonia flame are extended, and flames are stabilized near the inner shear layer. Emission measurement at the center of the quartz tube exit shows that NOx emissions are significantly reduced with plasma. It is surprising that NOx further decreases with the increase in discharge power and voltage. The tendency of NOx formation is the exact opposite of the results for methane/air flames in the identical setup.To understand the coupling effect between plasma kinetics and flame dynamics, NH2 * chemiluminescence and OH planar laser-induced fluorescence (PLIF) of ammonia/air flames are measured at different conditions. With the increase of discharge voltage or discharge power, both NH2 * chemiluminescence intensity and OH PLIF signal intensity increase, and this observation may explain the improved stabilization of ammonia flames. At very lean conditions (equivalence ratio between 0.48 and 0.57, no visible flame existed), both NH2* chemiluminescence and OH PLIF signals are observed in the proximity of electrode region with plasma activation. If air is replaced by nitrogen (N2), NH2 * chemiluminescence is measurable but extremely weak. As the oxygen (O2) concentration in the oxidizer stream gradually increases, NH2* chemiluminescence intensity increases linearly with O2 concentration under plasma activation. This finding indicates that the NH2* production in the plasma-assisted ammonia oxidation process is possibly related to the production of OH or oxygen-related species. The direct electron impact on NH2* production might be secondary.Finally, the effects of non-thermal plasma on low-pressure (20 Torr) ammonia pyrolysis and oxidation are explored. A dielectric barrier discharge (DBD) flow reactor is employed to decompose and oxidize ammonia. Stable species are measured 13.5 cm downstream from the flow reactor using electron ionization molecular beam mass spectroscopy (EI-MBMS). In the study of ammonia pyrolysis without oxygen, premixed ammonia and argon (Ar) at room temperature are supplied through the flow reactor. Productions of nitrogen (N2) and hydrogen (H2) are observed with the consumption of ammonia. The hydrogen yield increases with increasing plasma peak voltage, residence time in the flow reactor, and ammonia concentration in the feed gas. To study ammonia oxidation, a mixture of ammonia, oxygen (O2), and argon at room temperature is fed to the flow reactor. Ammonia oxidation by plasma produces mainly water (H2O) and nitrogen. Additionally, nitric oxide (NO) is measured under lean conditions. Unlike the tendency of hydrogen production in ammonia pyrolysis without oxygen, the mole fraction of NO emission decreases as the plasma peak voltage increases or the residence time in the DBD flow reactor becomes longer. In other words, NO production is attenuated with stronger plasma effects. Thus, a plasma-produced radical may prohibit NO production.The results of plasma-assisted ammonia combustion reported in this study show a dramatic difference from similar work using hydrocarbon fuels in which plasma promoted NOx emission. Therefore, the benefit of flame enhancement and NOx reduction with plasma may open the door of plasma-assisted ammonia combustion as a new direction for renewable and clean energy.
- 일반주제명
- Turbines
- 일반주제명
- Photographs
- 일반주제명
- Natural gas
- 일반주제명
- Petroleum engineering
- 기본자료저록
- Dissertations Abstracts International. 87-05B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
008260203s2023 us c eng d■001000017366004
■00520260209102912
■006m o d
■007cr#unu||||||||
■020 ▼a9798265403889
■035 ▼a(MiAaPQ)AAI32316146
■035 ▼a(MiAaPQ)GeorgiaTech72681
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a621.165
■1001 ▼aChoe, Jinhoon.
■24510▼aInvestigation of Plasma-Assisted Combustion in Swirling Flow Conditions
■260 ▼a[Sl]▼bGeorgia Institute of Technology▼c2023
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2023
■300 ▼a159 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 87-05, Section: B.
■500 ▼aAdvisor: Sun, Wenting.
■5021 ▼aThesis (Ph.D.)--Georgia Institute of Technology, 2023.
■520 ▼aThis study presents the effect of a nanosecond pulsed plasma on premixed methane/air and ammonia/air flames in a model gas turbine dump combustor with an annular swirling flow. A hysteresis phenomenon on blowoff is observed in the study of methane/air flames. Therefore, the lean blowoff limit is not uniquely defined. This hysteresis phenomenon depends on the initial value of the equivalence ratio at which the flame is ignited and the air velocity. Different methane/air flame morphologies are also observed depending on the equivalence ratio and the region where the flame is stabilized. If a nanosecond pulsed plasma is applied at the combustor nozzle exit, a stable inner shear layer flame is always observed. The lean blowoff limit is significantly extended, and the hysteresis phenomenon disappears with plasma activation. This indicates that plasma provides an additional mechanism for flame stabilization. It is found that plasma activation increases NOx concentration and decreases CO concentration through emission analysis.Ammonia (NH3) is a carbon-free fuel with high hydrogen content. However, the application of ammonia/air combustion has two significant challenges: high NOx emission and poor flame stability. This study also presents the effects of the nanosecond pulsed plasma on ammonia/air flames to overcome these two challenges. Both lean blowoff limits and NOx emission are investigated in a premixed swirl burner with nanosecond pulsed plasma. With plasma activation, the lean blowoff limits of ammonia flame are extended, and flames are stabilized near the inner shear layer. Emission measurement at the center of the quartz tube exit shows that NOx emissions are significantly reduced with plasma. It is surprising that NOx further decreases with the increase in discharge power and voltage. The tendency of NOx formation is the exact opposite of the results for methane/air flames in the identical setup.To understand the coupling effect between plasma kinetics and flame dynamics, NH2 * chemiluminescence and OH planar laser-induced fluorescence (PLIF) of ammonia/air flames are measured at different conditions. With the increase of discharge voltage or discharge power, both NH2 * chemiluminescence intensity and OH PLIF signal intensity increase, and this observation may explain the improved stabilization of ammonia flames. At very lean conditions (equivalence ratio between 0.48 and 0.57, no visible flame existed), both NH2* chemiluminescence and OH PLIF signals are observed in the proximity of electrode region with plasma activation. If air is replaced by nitrogen (N2), NH2 * chemiluminescence is measurable but extremely weak. As the oxygen (O2) concentration in the oxidizer stream gradually increases, NH2* chemiluminescence intensity increases linearly with O2 concentration under plasma activation. This finding indicates that the NH2* production in the plasma-assisted ammonia oxidation process is possibly related to the production of OH or oxygen-related species. The direct electron impact on NH2* production might be secondary.Finally, the effects of non-thermal plasma on low-pressure (20 Torr) ammonia pyrolysis and oxidation are explored. A dielectric barrier discharge (DBD) flow reactor is employed to decompose and oxidize ammonia. Stable species are measured 13.5 cm downstream from the flow reactor using electron ionization molecular beam mass spectroscopy (EI-MBMS). In the study of ammonia pyrolysis without oxygen, premixed ammonia and argon (Ar) at room temperature are supplied through the flow reactor. Productions of nitrogen (N2) and hydrogen (H2) are observed with the consumption of ammonia. The hydrogen yield increases with increasing plasma peak voltage, residence time in the flow reactor, and ammonia concentration in the feed gas. To study ammonia oxidation, a mixture of ammonia, oxygen (O2), and argon at room temperature is fed to the flow reactor. Ammonia oxidation by plasma produces mainly water (H2O) and nitrogen. Additionally, nitric oxide (NO) is measured under lean conditions. Unlike the tendency of hydrogen production in ammonia pyrolysis without oxygen, the mole fraction of NO emission decreases as the plasma peak voltage increases or the residence time in the DBD flow reactor becomes longer. In other words, NO production is attenuated with stronger plasma effects. Thus, a plasma-produced radical may prohibit NO production.The results of plasma-assisted ammonia combustion reported in this study show a dramatic difference from similar work using hydrocarbon fuels in which plasma promoted NOx emission. Therefore, the benefit of flame enhancement and NOx reduction with plasma may open the door of plasma-assisted ammonia combustion as a new direction for renewable and clean energy.
■590 ▼aSchool code: 0078.
■650 4▼aTurbines
■650 4▼aPhotographs
■650 4▼aNatural gas
■650 4▼aPetroleum engineering
■690 ▼a0765
■71020▼aGeorgia Institute of Technology.
■7730 ▼tDissertations Abstracts International▼g87-05B.
■790 ▼a0078
■791 ▼aPh.D.
■792 ▼a2023
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17366004▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
