摘要
使用直接数值模拟和详细化学反应机理研究了三维甲烷/空气湍流分层射流火焰.火焰呈V形,由稳燃棒进行稳燃.分析了不同流向位置处的火焰分层现象,在上游出现了前支撑火焰,下游出现了后支撑火焰.下游火焰的燃烧强度大于上游火焰的.通过对火焰结构的进一步分析,发现前支撑燃烧向后支撑燃烧的转变与H2基团在产物侧的积累有关.同时,后支撑火焰中出现了H2基团的优先输运现象,这增强了预热区的化学反应强度,从而增强了燃烧强度.对火焰位移速度与切向应变率的联合分布的分析表明,较小的切向应变率对应较大的位移速度.与下游相比,上游负火焰位移速度的概率较大,这是由较大的正切向应变率造成的.
Direct numerical simulation of three-dimensional methane/air turbulent stratified jet flame was carried out based on detailed chemical mechanism.The flame was stabilized by a hot rod and formed a V shape.The flame stratification at various streamwise locations was analyzed.It was found that the flame was front-supported in the upstream region and back-supported in the downstream region.The combustion intensity was stronger in the downstream region than in the upstream region.The flame structure was further analyzed and it was found that the change of combustion mode from the front-supported to the back-supported was related to the accumulation of H2 in the product region.It was also found that the preferential transport of H2 occurred in the back-supported flame,which enhanced the reaction intensity in the preheating zone and thus enhanced the combustion intensity.The joint distribution of tangential strain rate and flame displacement speed was explored.It was found that small values of tangential strain rate correspond to large values of displacement speed.Moreover,due to the larger values of tan-gential strain rate,the probability of negative flame displacement speed in the upstream region was larger than that in the downstream region.
作者
任嘉豪
王海鸥
罗坤
樊建人
Ren Jiahao;Wang Haiou;Luo Kun;Fan Jianren(State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China)
出处
《燃烧科学与技术》
CAS
CSCD
北大核心
2022年第6期673-678,共6页
Journal of Combustion Science and Technology
基金
国家自然科学基金资助项目(51976185)
国家自然科学基金优秀青年基金资助项目(52022091).
关键词
湍流燃烧
分层火焰
直接数值模拟
后支撑燃烧
turbulent combustion
stratified flame
direct numerical simulation
back-supported combustion
