Examination of differential diffusion effects in spatially-developing supersonic mixing layer hydrogen flames

IF 5.8 2区 工程技术 Q2 ENERGY & FUELS
Jieli Wei , Xu Zhu , Nana Wang
{"title":"Examination of differential diffusion effects in spatially-developing supersonic mixing layer hydrogen flames","authors":"Jieli Wei ,&nbsp;Xu Zhu ,&nbsp;Nana Wang","doi":"10.1016/j.combustflame.2025.114138","DOIUrl":null,"url":null,"abstract":"<div><div>Differential diffusion (DD) plays a crucial role in the fundamental understanding of combustion process, particular in the context of hydrogen or hydrogen-blended fuel flames. This paper intends to address whether the impact of DD on the flame stabilization in the turbulence-dominant supersonic flow can be negligible and if not, to elucidate its mechanisms. To this end, a spatially-developing supersonic non-premixed mixing layer hydrogen flame is simulated by large eddy simulations. Three distinct flow-chemistry interaction patterns: <em>laminar flow-chemistry, transition-chemistry</em>, and <em>turbulence-chemistry</em> are well designed within the mixing layer to examine the dependence of the DD effect on turbulence and its implications for flame stabilization. Results show that the importance of DD in flame-base zones of <em>transition-chemistry</em> and <em>turbulence-chemistry</em> interaction patterns is more pronounced than in <em>laminar flow-chemistry</em> one, even though their turbulence effects are more significant. The DD effect is observed to shorten the flame lift-off length and shift the leading point dynamic from a low-frequency to a high-frequency mode. Further “budget analysis” of transport- and chemistry- effect of DD shows that although the transport contribution of DD diminishes in turbulence-dominant flow-chemistry interaction patterns, the chemistry contribution of DD, i.e., sensitivity of the ignition delay time (IDT) to DD, is increased due to the low mixture temperature. Specifically, even a minor increase in the concentration of certain radicals, such as H, caused by DD can result in a significant reduction in IDT. This is primarily responsible for DD shortening the flame lift-off length within <em>transition-chemistry</em> and <em>turbulence-chemistry</em> interaction patterns. In <em>laminar flow-chemistry</em> pattern, DD facilitates the reaction to withstand high strain rates and in turn reducing the flame lift-off length.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114138"},"PeriodicalIF":5.8000,"publicationDate":"2025-04-01","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/S0010218025001762","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}
引用次数: 0

Abstract

Differential diffusion (DD) plays a crucial role in the fundamental understanding of combustion process, particular in the context of hydrogen or hydrogen-blended fuel flames. This paper intends to address whether the impact of DD on the flame stabilization in the turbulence-dominant supersonic flow can be negligible and if not, to elucidate its mechanisms. To this end, a spatially-developing supersonic non-premixed mixing layer hydrogen flame is simulated by large eddy simulations. Three distinct flow-chemistry interaction patterns: laminar flow-chemistry, transition-chemistry, and turbulence-chemistry are well designed within the mixing layer to examine the dependence of the DD effect on turbulence and its implications for flame stabilization. Results show that the importance of DD in flame-base zones of transition-chemistry and turbulence-chemistry interaction patterns is more pronounced than in laminar flow-chemistry one, even though their turbulence effects are more significant. The DD effect is observed to shorten the flame lift-off length and shift the leading point dynamic from a low-frequency to a high-frequency mode. Further “budget analysis” of transport- and chemistry- effect of DD shows that although the transport contribution of DD diminishes in turbulence-dominant flow-chemistry interaction patterns, the chemistry contribution of DD, i.e., sensitivity of the ignition delay time (IDT) to DD, is increased due to the low mixture temperature. Specifically, even a minor increase in the concentration of certain radicals, such as H, caused by DD can result in a significant reduction in IDT. This is primarily responsible for DD shortening the flame lift-off length within transition-chemistry and turbulence-chemistry interaction patterns. In laminar flow-chemistry pattern, DD facilitates the reaction to withstand high strain rates and in turn reducing the flame lift-off length.
研究空间发展超音速混合层氢焰中的差分扩散效应
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Combustion and Flame
Combustion and Flame 工程技术-工程:化工
CiteScore
9.50
自引率
20.50%
发文量
631
审稿时长
3.8 months
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.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信