Convoluted Intake Distortion Measurements Using Stereo Particle Image Velocimetry
Convoluted Intake Distortion Measurements Using Stereo Particle Image Velocimetry
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DOI：
10.2514/1.j055467
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发表时间：
2017-06-01
期刊：
影响因子：
2.5
通讯作者：
Menzies, Kevin R.
中科院分区：
文献类型：
--
作者：
Gil-Prieto, Daniel;MacManus, David G.;Menzies, Kevin R.
旋涡式航空发动机进气道内产生的非定常畸变流场会影响发动机的性能和可操作性。因此，有必要更好地了解s形进气道出口畸变流的复杂特性。这项工作提出了一个详细的分析基于同步，高空间分辨率测量的非定常涡流畸变使用立体粒子图像测速。研究了具有不同中心线偏移量的两种s型风管结构。高偏置导管表现出更高水平的动态和稳定涡流畸变，并且明显更倾向于与高涡流畸变相关的大块涡流模式。更多的离散畸变模式与局部高涡流水平和潜在的影响发动机的操作性被确定。用适当的正交分解方法观察了流场中最具能量的相干结构。发现了一种促进交替旋流切换机制的切换模式，并且主要与强旋流事件的发生有关。以垂直速度场扰动为特征的垂直模式促进了大多数双旋流畸变拓扑结构。假定它与中心线剪切层的失稳有关。
The unsteady distorted flowfields generated within convoluted aeroengine intakes can compromise the engine performance and operability. Therefore, there is a need for a better understanding of the complex characteristics of the distorted flow at the exit of S-shaped intakes. This work presents a detailed analysis of the unsteady swirl distortion based on synchronous, high-spatial-resolution measurements using stereoscopic particle image velocimetry. Two S-duct configurations with different centerline offsets are investigated. The high-offset duct shows greater levels of dynamic and steady swirl distortion and a notably greater tendency toward bulk swirl patterns associated with high swirl distortion. More discrete distortion patterns with locally high swirl levels and the potential to impact the engine operability are identified. The most energetic coherent structures of the flowfield are observed using proper orthogonal decomposition. A switching mode is identified that promotes the alternating swirl switching mechanism and is mostly associated with the occurrence of potent bulk swirl events. A vertical mode that characterizes a perturbation of the vertical velocity field promotes most of the twin swirl flow distortion topologies. It is postulated that it is associated with the unsteadiness of the centerline shear layer.