Abstract This paper presents a one-dimensional thermoacoustic model for a dump combustor in terms of two acoustic impedances just before and after a flame/area-expansion location. A key findings is that, as long as combustion instability is concerned, those two impedances fully crystallize the geometry of a combustor, steady operating conditions and inlet-outlet boundary conditions. From this impedance-based thermoacoustic model and a formulation of combustion instability as a robust stability problem, it is shown that the existence of either a low frequency impedance matching or a low resonance frequency of a flame chamber associated with a closed left boundary at a flame location, can promote combustion instability. A sufficient condition for combustion stability which requires no knowledge of a flame transfer function except its peak gain, is also presented. Our sufficient condition is shown to be less conservative than existing ones in literature. A numerical example is presented to illustrate our developments and findings.

中文翻译：

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从声阻抗角度分析燃烧不稳定性

摘要 本文根据火焰/区域扩展位置之前和之后的两个声阻抗，提出了倾卸式燃烧器的一维热声模型。一个重要的发现是，只要涉及燃烧不稳定性，这两个阻抗就完全体现了燃烧器的几何形状、稳定运行条件和入口-出口边界条件。从这个基于阻抗的热声模型和作为鲁棒稳定性问题的燃烧不稳定性公式，表明存在低频阻抗匹配或火焰室的低共振频率与火焰处的闭合左边界相关联。位置，可促进燃烧不稳定。燃烧稳定性的充分条件，除了峰值增益外，不需要任何火焰传递函数的知识，还介绍了。我们的充分条件被证明不如文献中现有的条件保守。提供了一个数值例子来说明我们的发展和发现。