高压甲烷射流对层流火焰作用的试验  

Experiment on the Effect of High-Pressure Methane Jet on Laminar Flame

作　　者：雷艳[1] 丁梦竹 仇滔[1] 李泳 刘佳星 赵宁[1] Lei Yan;Ding Mengzhu;Qiu Tao;Li Yong;Liu Jiaxing;Zhao Ning(Faculty of Environment and Life,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学环境与生命学部,北京100124

出　　处：《内燃机学报》2022年第2期113-118,共6页Transactions of Csice

基　　金：国家自然科学基金资助项目(91641106);内燃机可靠性国家重点实验室开放课题资助项目(Skler-201913).

摘　　要：高压气体燃料射流与引燃的层流火焰间的相互作用决定了天然气直喷发动机的着火稳定性.在定容燃烧弹中,用点火针点燃预混甲烷形成层流火焰,并在不同火焰半径时刻进行高压甲烷射流.采用高速纹影法测试了甲烷不同喷射延时τ对预混层流火焰的影响.结果表明:甲烷喷射延时τ决定了预混层流火焰等效半径R的发展,随着τ增大,预混层流火焰等效半径R增大;射流对层流火焰发展的影响与其作用于层流火焰时火焰等效半径有关,存在一个临界火焰等效半径R_(0),当R<R_(0)时,射流吹熄火焰;R=R_(0)时,甲烷射流吹熄预混层流火焰后仍可被引燃,火焰传播速度加快;R>R_(0)时,甲烷射流更容易引燃成湍流燃烧火焰,同时预混火焰未受射流干扰区域仍旧保持层流火焰,此时层流火焰、湍流燃烧火焰并存,火焰传播速度加快.The interaction between the high-pressure gas fuel jet and the pilot laminar flame determines the ignition stability of the direct injection natural gas engine.Based on a constant volume combustion vessel,the premixed methane was ignited by spark electrodes to form the laminar flame,and the high-pressure methane was injected into the under condition of varied laminar flame radius.By high-speed photographic schlieren method,the influences of methane injection delay timeτon the premixed ignition flame were tested.The results show that the methane injection delay timeτdetermines the development of the equivalent flame radius R of the premixed ignition flame.The R increases asτincreases.The effect of the jet on the laminar flame is related to the equivalent flame radius when the jet just contacts with the laminar flame,and there is a critical equivalent flame radius R_(0).As R<R_(0),the jet blows off the premixed flame.As R=R_(0),the methane jet just blows off the premixed flame,but it is ignited by the premixed pilot flame with a speed-up flame propagation velocity.Once R>R_(0),the methane jet is easy to be successfully ignited by the pilot flame to propagate as strong turbulent combustion flame.At the same time,the premixed flame maintains its laminar flame shape in the zone without interacting with the jet.Thus,both the laminar flame and the turbulent flame exist together,and the flame propagation velocity increases.

关 键 词：天然气直喷发动机 射流 层流火焰 

分 类 号：TK437[动力工程及工程热物理—动力机械及工程]