摘要
参考航空发动机燃烧室典型工况设计了微型模型非预混旋流燃烧室并进行了直接数值模拟,基于火焰因子对火焰标量特征进行了分析.研究发现,在非预混燃烧中,预混燃烧模态广泛存在且是放热的主要贡献者.不同工况中火焰面的分布位置和预混火焰的产生机制均存在显著差异.在贫燃工况中,火焰分布在内剪切层中,氧气优先向燃料侧输运从而在富燃料侧产生预混火焰;而在富燃工况中,火焰主要分布在外剪切层中,由于燃料中间产物优先向空气侧输运,预混火焰主要产生于富氧气侧.对标量通量的研究发现:非守恒标量(如Y_(CO_(2)))通量在各燃烧模态中均基本符合梯度假设;守恒标量(如混合分数Z)通量仅在预混燃烧模态中符合假设,在扩散火焰面附近不遵循这一假设.
According to the typical working condition of a combustor in an aircraft-engine,a micro-model nonpremixed swirling combustor was designed,and its direct numerical simulation was performed.In addition,the flame scalar characteristics were analyzed based on a flame index.It is found that the premixed combustion mode exists widely in non-premixed combustion,which is also the main contributor to heat release.There are significant differences in flame surface distribution and premixed flame generation mechanism under different working condi-tions.In the case of lean combustion,flame is distributed in the inner shear layer,and oxygen is preferentially transported to the fuel to generate the premixed flame.In comparison,flame is mainly distributed in the outer shear layer in the case of rich combustion,and the intermediate product of fuel is preferentially transported to air,where the premixed flame is mainly generated.The study of scalar flux shows that the non-conserved scalar(e.g.,Y_(CO_(2)))conforms to the gradient assumption in all combustion modes,while the conserved scalar(e.g.,mixture fraction Z)only conforms to this consumption in the premixed combustion mode,excluding the diffused combustion mode near the flame surface.
作者
肖华林
罗坤
金台
王海鸥
樊建人
Xiao Hualin;Luo Kun;Jin Tai;Wang Haiou;Fan Jianren(State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China;School of Aeronautics and Astronautics,Zhejiang University,Hangzhou 310027,China)
出处
《燃烧科学与技术》
CAS
CSCD
北大核心
2022年第2期170-176,共7页
Journal of Combustion Science and Technology
基金
国家自然科学基金重大研究计划资助项目(91741203).
关键词
直接数值模拟
非预混火焰
旋流燃烧室
火焰因子
标量通量
direct numerical simulation
non-premixed flame
swirling combustor
flame index
scalar flux
