{"title":"超音速流中空腔焰室的彩色和多波段成像","authors":"Seong-Young Lee, Timothy M. Ombrello","doi":"10.1016/j.proci.2024.105268","DOIUrl":null,"url":null,"abstract":"Utilizing time-resolved CH*/C* and multi-angle color flame imaging recorded at 1 kHz/22.5 kHz frequencies, this study investigates the dynamics and stabilization of supersonic flames in a cavity flameholder combustor at Mach 2, with ethylene fuel and air. A stagnation pressure of 289 kPa was used for the stable cavity burning experiments with fuel flow rates of 30, 60, and 90 slpm and 483 kPa for ignition transient experiments with fuel flow rates of 55 and 90 slpm, injecting fuel at the closeout ramp. The stagnation temperature was 597 K. Chemiluminescence analysis focused on the equivalence ratio (ER) and combustion intensity, while a fiber-based endoscope captured color flame image, informing on premixedness, flame structure, and flame surface density. Results from transient ignition showed that a progression from lean to stoichiometric, and ultimately to fuel-rich conditions was observed, with marked transitions occurring along the cavity floor. High-intensity CH* regions were consistently associated with fuel-rich zones. Digital flame coloration discrimination (DFCD) analysis provided insights into the mixing efficiency, affecting the flame color and structure. Despite reduced fuel flow rates significantly altering flame characteristics, such as thickness and the persistence of a 'W' flame structure, the shear layer remained a focal point for optimal combustion conditions. The study demonstrated that the shear layer's intense turbulent mixing is crucial for flame stability and structure, with chemiluminescence surface density (CSD) profiles suggesting balanced combustion at 60 and 90 slpm flow rates. However, an asymmetry of CSD at 30 slpm indicated a shift towards fuel-rich conditions at the burning surface, indicating potential instability and elevated blowout.","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":null,"pages":null},"PeriodicalIF":5.3000,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Color and multi-band imaging of a cavity-based flameholder in supersonic flow\",\"authors\":\"Seong-Young Lee, Timothy M. Ombrello\",\"doi\":\"10.1016/j.proci.2024.105268\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Utilizing time-resolved CH*/C* and multi-angle color flame imaging recorded at 1 kHz/22.5 kHz frequencies, this study investigates the dynamics and stabilization of supersonic flames in a cavity flameholder combustor at Mach 2, with ethylene fuel and air. A stagnation pressure of 289 kPa was used for the stable cavity burning experiments with fuel flow rates of 30, 60, and 90 slpm and 483 kPa for ignition transient experiments with fuel flow rates of 55 and 90 slpm, injecting fuel at the closeout ramp. The stagnation temperature was 597 K. Chemiluminescence analysis focused on the equivalence ratio (ER) and combustion intensity, while a fiber-based endoscope captured color flame image, informing on premixedness, flame structure, and flame surface density. Results from transient ignition showed that a progression from lean to stoichiometric, and ultimately to fuel-rich conditions was observed, with marked transitions occurring along the cavity floor. High-intensity CH* regions were consistently associated with fuel-rich zones. Digital flame coloration discrimination (DFCD) analysis provided insights into the mixing efficiency, affecting the flame color and structure. Despite reduced fuel flow rates significantly altering flame characteristics, such as thickness and the persistence of a 'W' flame structure, the shear layer remained a focal point for optimal combustion conditions. The study demonstrated that the shear layer's intense turbulent mixing is crucial for flame stability and structure, with chemiluminescence surface density (CSD) profiles suggesting balanced combustion at 60 and 90 slpm flow rates. However, an asymmetry of CSD at 30 slpm indicated a shift towards fuel-rich conditions at the burning surface, indicating potential instability and elevated blowout.\",\"PeriodicalId\":408,\"journal\":{\"name\":\"Proceedings of the Combustion Institute\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.3000,\"publicationDate\":\"2024-07-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Proceedings of the Combustion Institute\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://doi.org/10.1016/j.proci.2024.105268\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the Combustion Institute","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1016/j.proci.2024.105268","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
Color and multi-band imaging of a cavity-based flameholder in supersonic flow
Utilizing time-resolved CH*/C* and multi-angle color flame imaging recorded at 1 kHz/22.5 kHz frequencies, this study investigates the dynamics and stabilization of supersonic flames in a cavity flameholder combustor at Mach 2, with ethylene fuel and air. A stagnation pressure of 289 kPa was used for the stable cavity burning experiments with fuel flow rates of 30, 60, and 90 slpm and 483 kPa for ignition transient experiments with fuel flow rates of 55 and 90 slpm, injecting fuel at the closeout ramp. The stagnation temperature was 597 K. Chemiluminescence analysis focused on the equivalence ratio (ER) and combustion intensity, while a fiber-based endoscope captured color flame image, informing on premixedness, flame structure, and flame surface density. Results from transient ignition showed that a progression from lean to stoichiometric, and ultimately to fuel-rich conditions was observed, with marked transitions occurring along the cavity floor. High-intensity CH* regions were consistently associated with fuel-rich zones. Digital flame coloration discrimination (DFCD) analysis provided insights into the mixing efficiency, affecting the flame color and structure. Despite reduced fuel flow rates significantly altering flame characteristics, such as thickness and the persistence of a 'W' flame structure, the shear layer remained a focal point for optimal combustion conditions. The study demonstrated that the shear layer's intense turbulent mixing is crucial for flame stability and structure, with chemiluminescence surface density (CSD) profiles suggesting balanced combustion at 60 and 90 slpm flow rates. However, an asymmetry of CSD at 30 slpm indicated a shift towards fuel-rich conditions at the burning surface, indicating potential instability and elevated blowout.
期刊介绍:
The Proceedings of the Combustion Institute contains forefront contributions in fundamentals and applications of combustion science. For more than 50 years, the Combustion Institute has served as the peak international society for dissemination of scientific and technical research in the combustion field. In addition to author submissions, the Proceedings of the Combustion Institute includes the Institute''s prestigious invited strategic and topical reviews that represent indispensable resources for emergent research in the field. All papers are subjected to rigorous peer review.
Research papers and invited topical reviews; Reaction Kinetics; Soot, PAH, and other large molecules; Diagnostics; Laminar Flames; Turbulent Flames; Heterogeneous Combustion; Spray and Droplet Combustion; Detonations, Explosions & Supersonic Combustion; Fire Research; Stationary Combustion Systems; IC Engine and Gas Turbine Combustion; New Technology Concepts
The electronic version of Proceedings of the Combustion Institute contains supplemental material such as reaction mechanisms, illustrating movies, and other data.