In modern compressors, variable stator vanes are increasingly utilized. These vanes require a specific gap between their leading and trailing edges and the casing/hub to prevent contact during rotation. For multi-stage axial compressors employing variable stator vanes, understanding the impact of clearance variations on compressor performance is crucial during design. This study focuses on experimental research conducted on a high-pressure compressor equipped with variable stator vanes and bleed, using a real engine structure. The investigation delves into the loss characteristics and flow mechanisms within the variable mechanism's flow field. Results show that, with the identical penny diameter, increasing radial clearance initially decreases flow field loss, but then loss rises, reaching a minimum with a 2 mm (1.25% blade height) clearance. Conversely, with the same radial clearance, increasing penny diameter initially increases loss, which then decreases, with larger penny diameters resulting in smaller losses. Based on these findings, it can be inferred that a clearance of around 2 mm substantially reduces losses within the vane. Losses within 0–10% of the blade height from the endwall mainly stem from penny leakage vortex and their interaction with passage vortex, while losses within 10–20% of the blade height primarily arise from passage vortex, thus mitigating overall losses. The study demonstrates that, compared to zero-clearance vanes, variable stator vanes with a partial gap resulted in lower total pressure losses and better flow field control.

中文翻译：

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带泄气高压压缩机中可变定子叶片损耗和流动机制的实验研究


在现代压缩机中，可变定子叶片的使用越来越多。这些叶片需要在其前缘和后缘与外壳/轮毂之间留出特定的间隙，以防止在旋转过程中发生接触。对于采用可变定子叶片的多级轴流式压缩机，在设计过程中了解间隙变化对压缩机性能的影响至关重要。本研究的重点是使用真实的发动机结构对配备可变定子叶片和排放装置的高压压缩机进行的实验研究。该研究深入研究了可变机构流场内的损耗特性和流动机制。结果表明，在相同的便士直径下，增加径向间隙最初会降低流场损失，但随后损失会增加，在 2 毫米（1.25% 叶片高度）间隙时达到最小值。相反，在相同的径向游隙下，增加针筒直径最初会增加损耗，然后减少，针筒直径越大，损耗越小。根据这些发现，可以推断出大约 2 mm 的间隙大大减少了叶片内的损耗。端壁叶片高度 0-10% 以内的损失主要源于便士泄漏涡流及其与通道涡流的相互作用，而叶片高度 10-20% 以内的损失主要来自通道涡流，从而减轻了整体损失。研究表明，与零间隙叶片相比，具有部分间隙的可变定子叶片导致更低的总压力损失和更好的流场控制。