Asymptotic approach to combustion instability
Asymptotic approach to combustion instability
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燃烧不稳定性的渐近方法
DOI：
10.1098/rsta.2005.1565
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Xuesong Wu
中科院分区：
文献类型：
--
作者：
Xuesong Wu
本文在大活化能和小马赫数的假设下，给出了预混火焰燃烧不稳定性的一种渐近分析方法。整个流动由四个不同但完全相互作用的子区域组成，分别容纳化学反应、热传输、流体动力学和声学。推导了一个简化的系统来描述火焰和声学之间的复杂耦合，这是燃烧不稳定性的基础。利用渐近约化系统研究了Darrieus-Landau不稳定性与燃烧室纵向声模之间的弱非线性相互作用。一般的渐近公式包含了迎面而来的混合物中的焓涨落的影响。结果表明，一维焓涨落通过与火焰的相互作用产生声波，并可能导致火焰的参数不稳定。在失稳阈值下，分析了声波与参数不稳定性之间的相互耦合。
This paper presents an asymptotic approach to combustion instability in premixed flames under the assumptions of large activation energy and small Mach number. The entire flow consists of four distinct yet fully interactive sub-regions, which accommodate the chemical reaction, heat transport, hydrodynamics and acoustics, respectively. A reduced system was derived to describe the intricate coupling between the flame and acoustics that underlies the combustion instability. The asymptotically reduced system was employed to study the weakly nonlinear interaction between the Darrieus–Landau instability and the longitudinal acoustic mode of the combustion chamber. The general asymptotic formulation includes the influence of enthalpy fluctuation in the oncoming mixture. It is shown that one-dimensional enthalpy fluctuation, through its interaction with flame, produces sound waves, and may cause parametric instability of the flame. The mutual coupling between the sound wave and parametric instability is analysed at the instability thresholds.