Effects of impedance-boundary-controlled casing treatment on the fan performance with eccentric inlet swirl

IF 2.8 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science Pub Date : 2024-10-19 DOI:10.1016/j.expthermflusci.2024.111339

Xu Dong , Yuqing Wang , Jia Li , Chunwang Geng , Dakun Sun , Xiaofeng Sun

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Abstract

An eccentric inlet swirl, a source of circumferential non-uniformity in aero-engines, can compromise the stable operational range of the compression system and potentially jeopardize the safety of the entire flight vehicle. This study experimentally examined the additional effects of an eccentric inlet swirl on an axial fan in comparison with a concentric inlet condition. Then, the effectiveness of an impedance-boundary-controlled (IBC) casing treatment (CT) in extending the stable operating range of the fan under eccentric inlets is evaluated. Steady-state loading and prestall disturbance analyses were conducted using a five-hole probe and high-frequency response pressure transducers to elucidate the instability mechanisms of fans exposed to eccentric inlets. The findings indicate that the eccentric swirl generates localized over-loading regions around the circumference, where abnormal prestall disturbances amplify in amplitude across a frequency range of 0.3 to 0.5 times the blade passing frequency. These characteristics were mitigated when IBC CT was applied over the rotor tip, allowing the fan to operate under concentric inlet conditions. The IBC CT enhances the stall margin of the fan by 9.3–19.6% in response to a range of swirl inlet conditions, suggesting its potential to address the irregularity problems in fans/compressors. The mechanisms by which IBC CT extends the stall margin are discussed from the unique perspective of evaluating steady loading and system damping.

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阻抗边界控制套管处理对偏心进气漩涡风机性能的影响

偏心进气道漩涡是航空发动机圆周不均匀性的一个来源，会影响压缩系统的稳定运行范围，并可能危及整个飞行器的安全。本研究通过实验检验了偏心进气漩涡与同心进气条件相比对轴流风扇的额外影响。然后，评估了阻抗边界控制（IBC）套管处理（CT）在偏心进气道条件下延长风扇稳定工作范围的有效性。使用五孔探头和高频响应压力传感器进行了稳态加载和安装前扰动分析，以阐明暴露在偏心进气口下的风机的失稳机制。研究结果表明，偏心漩涡会在圆周产生局部过载区域，安装前的异常扰动会在叶片通过频率的 0.3 至 0.5 倍频率范围内放大振幅。在转子顶端应用 IBC CT 后，这些特性得到了缓解，使风机能够在同心进气条件下运行。在各种漩涡入口条件下，IBC CT 可将风扇的失速裕度提高 9.3%-19.6%，这表明它具有解决风扇/压缩机中不规则问题的潜力。本文从评估稳定载荷和系统阻尼的独特角度讨论了 IBC CT 扩大失速裕度的机制。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experimental Thermal and Fluid Science 工程技术-工程：机械

CiteScore

6.70

自引率

3.10%

发文量

159

审稿时长

34 days

期刊介绍： Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.