{"title":"层流/湍流转换中 CH4 和裂解 NH3 混合物非预混喷射火焰的升空特性","authors":"Dong Seok Jeon, Gyu Jin Hwang, Nam Il Kim","doi":"10.1016/j.combustflame.2024.113462","DOIUrl":null,"url":null,"abstract":"<div><p>With the increasing interest in ammonia combustion technologies, using cracked ammonia gas is becoming an essential strategy. This study examined the stabilization characteristics of non-premixed lifted flames using mixtures of methane and cracked ammonia gas. A surrogate fuel of cracked ammonia consisting of 75 % H<sub>2</sub> and 25 % N<sub>2</sub> was used. Significant variations in the lift-off characteristics were observed, including the transition from laminar to turbulent regime. Flame structures at the base were investigated by capturing simultaneous Schlieren and OH-PLIF images, and the flame stabilization mechanisms were investigated based on the interaction between the fuel jet flow and the flame structures. Stable flames were formed below the mixing core in the laminar flame regime. Their behavior can be explained in terms of flame quenching. Flame stabilization below the turbulent core regime was also investigated in detail. In addition, the experimental results with cracked ammonia gas were significantly different than the previous relationship between lift-off height and fuel jet velocity in the fully turbulent regime. Thus, an improved relationship is proposed to estimate reasonable lift-off heights for all mixtures of methane, propane, hydrogen, and cracked ammonia gas. Finally, the blowout limits were explained by the decrease in flame propagation velocity due to the reduced turbulent intensity along the jet stream.</p></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":null,"pages":null},"PeriodicalIF":5.8000,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Lift-off characteristics of non-premixed jet flames of CH4 and cracked NH3 mixtures in laminar/turbulent transition\",\"authors\":\"Dong Seok Jeon, Gyu Jin Hwang, Nam Il Kim\",\"doi\":\"10.1016/j.combustflame.2024.113462\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>With the increasing interest in ammonia combustion technologies, using cracked ammonia gas is becoming an essential strategy. This study examined the stabilization characteristics of non-premixed lifted flames using mixtures of methane and cracked ammonia gas. A surrogate fuel of cracked ammonia consisting of 75 % H<sub>2</sub> and 25 % N<sub>2</sub> was used. Significant variations in the lift-off characteristics were observed, including the transition from laminar to turbulent regime. Flame structures at the base were investigated by capturing simultaneous Schlieren and OH-PLIF images, and the flame stabilization mechanisms were investigated based on the interaction between the fuel jet flow and the flame structures. Stable flames were formed below the mixing core in the laminar flame regime. Their behavior can be explained in terms of flame quenching. Flame stabilization below the turbulent core regime was also investigated in detail. In addition, the experimental results with cracked ammonia gas were significantly different than the previous relationship between lift-off height and fuel jet velocity in the fully turbulent regime. Thus, an improved relationship is proposed to estimate reasonable lift-off heights for all mixtures of methane, propane, hydrogen, and cracked ammonia gas. Finally, the blowout limits were explained by the decrease in flame propagation velocity due to the reduced turbulent intensity along the jet stream.</p></div>\",\"PeriodicalId\":280,\"journal\":{\"name\":\"Combustion and Flame\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.8000,\"publicationDate\":\"2024-05-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Combustion and Flame\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0010218024001718\",\"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":"Combustion and Flame","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0010218024001718","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}
Lift-off characteristics of non-premixed jet flames of CH4 and cracked NH3 mixtures in laminar/turbulent transition
With the increasing interest in ammonia combustion technologies, using cracked ammonia gas is becoming an essential strategy. This study examined the stabilization characteristics of non-premixed lifted flames using mixtures of methane and cracked ammonia gas. A surrogate fuel of cracked ammonia consisting of 75 % H2 and 25 % N2 was used. Significant variations in the lift-off characteristics were observed, including the transition from laminar to turbulent regime. Flame structures at the base were investigated by capturing simultaneous Schlieren and OH-PLIF images, and the flame stabilization mechanisms were investigated based on the interaction between the fuel jet flow and the flame structures. Stable flames were formed below the mixing core in the laminar flame regime. Their behavior can be explained in terms of flame quenching. Flame stabilization below the turbulent core regime was also investigated in detail. In addition, the experimental results with cracked ammonia gas were significantly different than the previous relationship between lift-off height and fuel jet velocity in the fully turbulent regime. Thus, an improved relationship is proposed to estimate reasonable lift-off heights for all mixtures of methane, propane, hydrogen, and cracked ammonia gas. Finally, the blowout limits were explained by the decrease in flame propagation velocity due to the reduced turbulent intensity along the jet stream.
期刊介绍:
The mission of the journal is to publish high quality work from experimental, theoretical, and computational investigations on the fundamentals of combustion phenomena and closely allied matters. While submissions in all pertinent areas are welcomed, past and recent focus of the journal has been on:
Development and validation of reaction kinetics, reduction of reaction mechanisms and modeling of combustion systems, including:
Conventional, alternative and surrogate fuels;
Pollutants;
Particulate and aerosol formation and abatement;
Heterogeneous processes.
Experimental, theoretical, and computational studies of laminar and turbulent combustion phenomena, including:
Premixed and non-premixed flames;
Ignition and extinction phenomena;
Flame propagation;
Flame structure;
Instabilities and swirl;
Flame spread;
Multi-phase reactants.
Advances in diagnostic and computational methods in combustion, including:
Measurement and simulation of scalar and vector properties;
Novel techniques;
State-of-the art applications.
Fundamental investigations of combustion technologies and systems, including:
Internal combustion engines;
Gas turbines;
Small- and large-scale stationary combustion and power generation;
Catalytic combustion;
Combustion synthesis;
Combustion under extreme conditions;
New concepts.