Jingru Zheng , Xiaolei Zhang , Suk Ho Chung , Longhua Hu
{"title":"氨/烃混合燃料喷射火焰的火焰高度和辐射特性实验研究","authors":"Jingru Zheng , Xiaolei Zhang , Suk Ho Chung , Longhua Hu","doi":"10.1016/j.combustflame.2024.113517","DOIUrl":null,"url":null,"abstract":"<div><p>Ammonia is considered as a renewable fuel and expected to play an essential role in coping with the energy crisis and climate change. Because of low combustion rate and high NO emission of ammonia, many studies focused on the characteristics of ammonia/hydrocarbon mixture fuels. However, the flame height and radiation characteristics of jet flames of ammonia and hydrocarbon mixture fuels have not been systematically studied yet. In this work, hydrocarbon fuels of methane and ethylene are mixed with ammonia for the fuel mixing ratio in the range of 0 to 50 %. Results show that the flame height increases with heat release rate (HRR) but changes little with the concentration of ammonia. The previous physical models for turbulent jet flames based on an integral approach can basically predict the flame height for heat release rate larger than 2.7 kW and a semi empirical formula based on dimensional analysis is verified well in predicting the flame height with the flame Froude number for Fr<sub>f</sub> > 0.05. For laminar flame heights, a model is proposed here considering the buoyancy effect which predicts well for CH<sub>4</sub>/NH<sub>3</sub> flame with total flow rate smaller than 5 L/min. For thermal radiation characteristics, the radiation fraction decreases with the ammonia mixing ratio increases. A consistent transitional value in predicting the radiation fraction is observed, irrespective of fuel type, which is mainly due to the reduction of soot during the transition from laminar to turbulent flames. The influence of ammonia on the flame radiation fraction of CH<sub>4</sub>/NH<sub>3</sub> flames normalized by that of pure hydrocarbon fuel (<span><math><mrow><msub><mi>χ</mi><mi>R</mi></msub><mo>/</mo><msub><mi>χ</mi><msub><mi>R</mi><mn>0</mn></msub></msub></mrow></math></span>) can be correlated by the mixing ratio. For C<sub>2</sub>H<sub>4</sub>/NH<sub>3</sub> flames, the influence of ammonia on the dimensionless radiation fraction is the result of the coupling effect of mixing fraction and strain rate. A correlation is proposed considering the effects of ammonia addition on radiation fraction in relation to Reynolds number, which is shown to correlate well the experimental results.</p></div><div><h3>Novelty and significance statement</h3><p>As ammonia/hydrocarbon fuel mixtures can reduce the emission of carbon dioxide, it can play an essential role during the transition to a non-carbonization society. Considering a fundamental importance of jet flames and a fire hazard scenario in case of fuel leakage, the present study investigates the effect of ammonia addition on the flame height and flame radiation fraction for ammonia/hydrocarbon fuel mixtures. We test the physical model of Quintiere and a semi empirical formula of Delichatsios in predicting the turbulent flame height of ammonia/hydrocarbon mixture fuels. A normalized model is proposed to describe the effect of adding ammonia on radiation fraction in relation to the Reynolds number. Our results provide necessary experimental data and models for further study on ammonia/hydrocarbon mixture fuel flames.</p></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":null,"pages":null},"PeriodicalIF":5.8000,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Experimental study on flame height and radiation characteristics in jet flames with ammonia/hydrocarbon mixture fuels\",\"authors\":\"Jingru Zheng , Xiaolei Zhang , Suk Ho Chung , Longhua Hu\",\"doi\":\"10.1016/j.combustflame.2024.113517\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Ammonia is considered as a renewable fuel and expected to play an essential role in coping with the energy crisis and climate change. Because of low combustion rate and high NO emission of ammonia, many studies focused on the characteristics of ammonia/hydrocarbon mixture fuels. However, the flame height and radiation characteristics of jet flames of ammonia and hydrocarbon mixture fuels have not been systematically studied yet. In this work, hydrocarbon fuels of methane and ethylene are mixed with ammonia for the fuel mixing ratio in the range of 0 to 50 %. Results show that the flame height increases with heat release rate (HRR) but changes little with the concentration of ammonia. The previous physical models for turbulent jet flames based on an integral approach can basically predict the flame height for heat release rate larger than 2.7 kW and a semi empirical formula based on dimensional analysis is verified well in predicting the flame height with the flame Froude number for Fr<sub>f</sub> > 0.05. For laminar flame heights, a model is proposed here considering the buoyancy effect which predicts well for CH<sub>4</sub>/NH<sub>3</sub> flame with total flow rate smaller than 5 L/min. For thermal radiation characteristics, the radiation fraction decreases with the ammonia mixing ratio increases. A consistent transitional value in predicting the radiation fraction is observed, irrespective of fuel type, which is mainly due to the reduction of soot during the transition from laminar to turbulent flames. The influence of ammonia on the flame radiation fraction of CH<sub>4</sub>/NH<sub>3</sub> flames normalized by that of pure hydrocarbon fuel (<span><math><mrow><msub><mi>χ</mi><mi>R</mi></msub><mo>/</mo><msub><mi>χ</mi><msub><mi>R</mi><mn>0</mn></msub></msub></mrow></math></span>) can be correlated by the mixing ratio. For C<sub>2</sub>H<sub>4</sub>/NH<sub>3</sub> flames, the influence of ammonia on the dimensionless radiation fraction is the result of the coupling effect of mixing fraction and strain rate. A correlation is proposed considering the effects of ammonia addition on radiation fraction in relation to Reynolds number, which is shown to correlate well the experimental results.</p></div><div><h3>Novelty and significance statement</h3><p>As ammonia/hydrocarbon fuel mixtures can reduce the emission of carbon dioxide, it can play an essential role during the transition to a non-carbonization society. Considering a fundamental importance of jet flames and a fire hazard scenario in case of fuel leakage, the present study investigates the effect of ammonia addition on the flame height and flame radiation fraction for ammonia/hydrocarbon fuel mixtures. We test the physical model of Quintiere and a semi empirical formula of Delichatsios in predicting the turbulent flame height of ammonia/hydrocarbon mixture fuels. A normalized model is proposed to describe the effect of adding ammonia on radiation fraction in relation to the Reynolds number. Our results provide necessary experimental data and models for further study on ammonia/hydrocarbon mixture fuel flames.</p></div>\",\"PeriodicalId\":280,\"journal\":{\"name\":\"Combustion and Flame\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.8000,\"publicationDate\":\"2024-05-24\",\"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/S0010218024002256\",\"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/S0010218024002256","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}
Experimental study on flame height and radiation characteristics in jet flames with ammonia/hydrocarbon mixture fuels
Ammonia is considered as a renewable fuel and expected to play an essential role in coping with the energy crisis and climate change. Because of low combustion rate and high NO emission of ammonia, many studies focused on the characteristics of ammonia/hydrocarbon mixture fuels. However, the flame height and radiation characteristics of jet flames of ammonia and hydrocarbon mixture fuels have not been systematically studied yet. In this work, hydrocarbon fuels of methane and ethylene are mixed with ammonia for the fuel mixing ratio in the range of 0 to 50 %. Results show that the flame height increases with heat release rate (HRR) but changes little with the concentration of ammonia. The previous physical models for turbulent jet flames based on an integral approach can basically predict the flame height for heat release rate larger than 2.7 kW and a semi empirical formula based on dimensional analysis is verified well in predicting the flame height with the flame Froude number for Frf > 0.05. For laminar flame heights, a model is proposed here considering the buoyancy effect which predicts well for CH4/NH3 flame with total flow rate smaller than 5 L/min. For thermal radiation characteristics, the radiation fraction decreases with the ammonia mixing ratio increases. A consistent transitional value in predicting the radiation fraction is observed, irrespective of fuel type, which is mainly due to the reduction of soot during the transition from laminar to turbulent flames. The influence of ammonia on the flame radiation fraction of CH4/NH3 flames normalized by that of pure hydrocarbon fuel () can be correlated by the mixing ratio. For C2H4/NH3 flames, the influence of ammonia on the dimensionless radiation fraction is the result of the coupling effect of mixing fraction and strain rate. A correlation is proposed considering the effects of ammonia addition on radiation fraction in relation to Reynolds number, which is shown to correlate well the experimental results.
Novelty and significance statement
As ammonia/hydrocarbon fuel mixtures can reduce the emission of carbon dioxide, it can play an essential role during the transition to a non-carbonization society. Considering a fundamental importance of jet flames and a fire hazard scenario in case of fuel leakage, the present study investigates the effect of ammonia addition on the flame height and flame radiation fraction for ammonia/hydrocarbon fuel mixtures. We test the physical model of Quintiere and a semi empirical formula of Delichatsios in predicting the turbulent flame height of ammonia/hydrocarbon mixture fuels. A normalized model is proposed to describe the effect of adding ammonia on radiation fraction in relation to the Reynolds number. Our results provide necessary experimental data and models for further study on ammonia/hydrocarbon mixture fuel flames.
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.