Interaction of rotating instabilities and stall in axial compressors

轴流压缩机中旋转不稳定性和失速的相互作用

• 批准号: 426295581
• 负责人: Professor Dr.-Ing. Dieter Peitsch
• 金额: --
• 依托单位: Fachgebiet Luftfahrtantriebe
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/426295581?language=en
• 关键词: Interaction; rotating; instabilities; stall; axial

The proposed project focuses on Rotating Instability (RI), which is known as a prestall instability in axial compressors. Referring to own recent experimental and numerical investigations, the physical mechanism of RI needs to be reflected on a generic model. Based on a systematical reduction of necessary boundary conditions, a Kelvin-Helmholtz-Instability is to be generated in an annulus where the disturbances propagate circumferentially. Afterwards pressure fluctuations being induced by the Kelvin-Helmholtz-Instability will be investigated using established analysis methods for the identification of RI. In order to extend the scope of parameters, the impact of periodical wakes coming from an upstream blade row onto the formation of RI will be investigated. In detail, the main objective is to analyze the influence of specific excitation frequencies on spectral, modal and time-resolved RI characteristics. In a multidisciplinary approach, a possible influence of RI through a targeted adjustment of the number of blades would also provide a great scientific benefit in the field of aeroelasticity of turbomachinery. It is known that RI can be one of the reasons for non-synchronous blade vibrations. In addition, the extremely short-timed inception process of rotating stall will be investigated under the additional influence of RI. It will be clarified whether RI is provoking the development of stall cells and which driving mechanisms are involved in this process. In this context, the interaction between RI and well-known inception mechanisms such as "spikes" or "modes" will be analyzed. The results have great potential to contribute significantly to the subject of rotating stall inception. Over the last decades the topic RI is part of lively but also controversial discussions. Even the term "Rotating Instability" was considered inappropriate by parts of the community. Thus, the proposed project supports an unambiguous classification of RI into the field of "compressor instabilities" and "stall inception".

该项目的重点是旋转不稳定性（RI），这是众所周知的轴流压气机的失速前不稳定性。参考自己最近的实验和数值研究，RI的物理机制需要反映在一个通用的模型。基于对必要边界条件的系统简化，在扰动沿圆周传播的环形空间中产生Kelvin-Helmholtz不稳定。之后，将使用已建立的用于识别RI的分析方法来研究由开尔文-亥姆霍兹不稳定性引起的压力波动。为了扩大参数范围，将研究来自上游叶片排的周期性尾流对RI形成的影响。详细地，主要目标是分析特定的激励频率的频谱，模态和时间分辨RI特性的影响。在多学科方法中，通过有针对性地调整叶片数量，RI可能产生的影响也将在涡轮机气动弹性领域提供巨大的科学效益。已知RI可能是非同步叶片振动的原因之一。此外，在附加阻力影响下，还将研究旋转失速的短时起始过程。这将是澄清是否RI挑起发展的失速细胞和驱动机制参与了这一进程。在这种情况下，RI和众所周知的初始机制，如“尖峰”或“模式”之间的相互作用将进行分析。结果有很大的潜力，有助于显着旋转失速起始的主题。在过去的几十年里，国际扶轮的话题是活跃但也有争议的讨论的一部分。甚至“旋转不稳定性”一词也被部分社区认为是不合适的。因此，建议的项目支持一个明确的分类RI到“压气机不稳定性”和“失速起始”领域。