摘要
采用直接数值模拟方法研究非预混状态的NH_(3)/Air混合层在层流和湍流条件下的自点火、火焰传播和生成NO过程.添加氢气、压力增加和湍流混合都会加快氨气的自点火过程.NH_(2)、HNO和OH 3个自由基可以分别表征点火的诱导和热释放阶段.层流和湍流条件下,释热率都会在火焰传播末期产生两个峰值,即分层现象:小峰值区主要与OH的基元反应有关,大峰值区主要与NH_(2)和HNO的基元反应有关.添加氢气和湍流都会提高NO的生成量.最大NO数值曲线随时间会先增大后减小,两个阶段由NO的反应项和扩散项分别主导.
Direct numerical simulation was applied to study the auto-ignition,flame propagation and NO formation for non-premixed NH_(3)/Air mixing layer under laminar and turbulent conditions.The auto-ignition was accelerated by hydrogen addition to the initial fuel of ammonia,elevated pressure and turbulent mixing.Two stages of auto-ignition,induction and thermal runaway,were clearly characterized by three radicals,NH_(2),HNO and OH.Two peaks occurred for heat release at the end of flame propagation in both laminar and turbulent cases,which was known as the stratification phenomenon.The region of small peak was mainly formed by the elementary reactions of OH,and that of large peak was mainly formed by those of NH_(2) and HNO.NO formation was enhanced by hydrogen addition and turbulence.The maximum concentration of NO varied with time,increasing first and then decreasing.The two stages were primarily governed by the reaction and diffusion terms of NO,respectively.
作者
杨文豪
罗开红
Yang Wenhao;KHLuo(Center for Combustion Energy,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;Hydrogen Energy Division,Zoomlion New Energy Technology Development Company,Changsha 410013,China)
出处
《燃烧科学与技术》
CAS
CSCD
北大核心
2024年第5期447-456,共10页
Journal of Combustion Science and Technology
基金
国家自然科学基金资助项目(52250710681).
关键词
氨气混合层
自点火
一氧化氮生成
直接数值模拟
ammonia mixing layer
auto-ignition
NO formation
direct numerical simulations
