Thermoacoustic instability is a flow instability that arises due to a two-way coupling between acoustic waves and unsteady heat release rate. It can cause damaging, large-amplitude oscillations in the combustors of gas turbines, aeroengines, rocket engines, etc., and the transition to decarbonized fuels is likely to introduce new thermoacoustic instability problems. With a focus on practical thermoacoustic instability problems, especially in gas turbine combustors, this review presents the common types of combustor and burner geometry used. It discusses the relevant flow physics underpinning their acoustic and unsteady flame behaviors, including how these differ across combustor and burner types. Computational tools for predicting thermoacoustic instability can be categorized into direct computational approaches, in which a single flow simulation resolves all of the most important length scales and timescales, and coupled/hybrid approaches, which couple separate computational treatments for the acoustic waves and flame, exploiting the large disparity in length scales associated with these. Examples of successful computational prediction of thermoacoustic instability in realistic combustors are given, along with outlooks for future research in this area.

中文翻译：

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燃烧室中的热声不稳定性


热声不稳定性是由于声波和不稳定热释放速率之间的双向耦合而引起的流动不稳定性。它会在燃气轮机、航空发动机、火箭发动机等的燃烧室中引起破坏性的大振幅振荡，并且向脱碳燃料的过渡可能会引入新的热声不稳定性问题。本文重点介绍了实际的热声不稳定问题，尤其是燃气轮机燃烧室，介绍了常用的燃烧室和燃烧器几何形状类型。它讨论了支撑其声学和非稳态火焰行为的相关流动物理学，包括它们在不同燃烧室和燃烧器类型中的差异。用于预测热声不稳定性的计算工具可分为直接计算方法和耦合/混合方法，其中单个流动模拟解决了所有最重要的长度尺度和时间尺度，以及耦合/混合方法，其中耦合了声波和火焰的单独计算处理，利用了与它们相关的长度尺度的巨大差异。给出了实际燃烧器中热声不稳定性的成功计算预测示例，并展望了该领域的未来研究。