Disturbance Energy Budget of Turbulent Swirling Premixed Flame in a Cuboid Combustor
Disturbance Energy Budget of Turbulent Swirling Premixed Flame in a Cuboid Combustor
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长方体燃烧室中湍流旋流预混火焰的扰动能量收支
DOI：
10.1016/j.proci.2016.08.033
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发表时间：
2017
影响因子：
3.4
通讯作者：
Mamoru Tanahashi
中科院分区：
文献类型：
--
作者：
Kozo Aoki;Masayasu Shimura;Yoshitsugu Naka;Mamoru Tanahashi
为了阐明基于精确扰动能量收支的燃烧振荡现象，本文对氢气-空气湍流旋流预混火焰进行了三维直接数值模拟（DNS），详细考虑了湍流预混火焰的动力学机制以及传输和热特性对温度的依赖性。在两个旋流数（S= 0.6和1.2）下的化学计量和贫工况进行了研究。对于所有计算条件，精确的扰动能量预算接近92%以上。对源项贡献的研究表明，涡旋数影响某些源项的贡献等级，而当量比影响扰动能量时间导数值的波动幅度。结果表明，与熵涨落和热源有关的源项分别是扰动能量增长和衰减的主要贡献者。除了这些主要的条款，源项有关的非平衡燃烧化学也被确定为是有影响的扰动能量的时间演化。根据上述几种重要扰动源的时均分布，讨论了扰动能量产生与火焰特性之间的关系。
In order to clarify combustion oscillation based on the exact disturbance energy budget, three-dimensional direct numerical simulations (DNS) of hydrogen–air turbulent swirling premixed flames are conducted in this study, considering a detailed kinetic mechanism and temperature dependencies of transport and thermal properties. Stoichiometric and lean conditions under two swirl numbers (S= 0.6 and 1.2) are investigated. The exact disturbance energy budget is closed to more than 92% for all computational conditions. Investigation of source term contributions reveals that the swirl number affects the order of contribution levels of some sources, while the equivalence ratio influences the fluctuation amplitude of the time derivative value of disturbance energy. It is shown that source terms related to fluctuations of entropy and heat sources are major contributors to disturbance energy growth and decay, respectively. In addition to these major terms, source terms related to non-equilibrium combustion chemistry are also determined to be influential to the time evolution of disturbance energy. The relation between disturbance energy generation and flame characteristics is discussed, based on the time–averaged distributions of some of the abovementioned important sources.