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Effects of Tip Leakage Vortex Breakdown on Flow Field in Turbomachinery Blade Row

叶尖泄漏涡击穿对透平机械叶排流场的影响

基本信息

批准号：
10650181
负责人：
FURUKAWA Masato
金额：
$ 2.18万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650181/
关键词：
Turbomachinery Blade Row Tip Leakage Vortex Vortex Breakdown Compressor Blade Tip Flow

项目摘要

The tip leakage vertex rolled up near the leading edge takes on the spiral-type breakdown in the fore part of the rotor passage at the near-stall conditions. The onset of the leakage vortex breakdown causes the drastic changes in the nature of the leakage vortex: downstream of the breakdown onset, the leakage vortex twists and turns violently with time, and has no feature of the streamwise slender vortex. The large movement of the leakage vortex gives rise to a strong interaction of the leakage vortex with the pressure surface of the adjacent blade. Although the interaction causes no separation of the blade boundary layer, the effects of the leakage vortex breakdown play a major role in the unsteady flow nature near the rotor tip at the near-stall conditions.The spiral-type breakdown of the tip leakage vortex brings about the anomalous flow phenomena in the leakage flow field at the near-stall conditions: no rolling-up of the leakage vortex downstream of the rotor, disappearance of the casing wall pressure trough corresponding to the leakage vortex, large spread of the low-energy fluid accumulating on the pressure side, and large pressure fluctuation on the pressure side.As the low rate is decreased further from the near-stall conditions, the movement of the tip leakage vortex due to its breakdown becomes so larger that the leakage vortex interacts with the suction surface as well as the pressure one. The interaction gives rise to the three-dimensional separation of the suction surface boundary layer near the tip. As a result, the total pressure rise across the rotor decreases drastically. It is found that the stall in the compressor rotor can be caused by the effect of the leakage vortex breakdown.

近失速状态下，叶尖泄漏涡在前缘附近卷起，在转子通道前部呈螺旋型破裂。泄漏涡破裂的发生使泄漏涡的性质发生了剧烈的变化：在破裂发生后，泄漏涡随时间发生剧烈的扭曲，不再具有流向细长涡的特征。泄漏涡的大幅度运动引起泄漏涡与相邻叶片压力面的强烈相互作用。虽然这种干扰不会引起叶片边界层的分离，但泄漏涡破裂的影响对近失速条件下转子叶尖附近的非定常流动性质起着主要作用，叶尖泄漏涡的螺旋型破裂导致近失速条件下泄漏流场的异常流动现象：转子下游的泄漏涡没有卷起，与泄漏涡相对应的机匣壁压力槽消失，积聚在压力侧的低能流体大范围扩散，随着低速比从近失速状态进一步降低，叶尖泄漏涡破裂后的运动变得更大，泄漏涡不仅与压力面相互作用，而且与吸力面相互作用。这种相互作用引起叶尖附近吸力面边界层的三维分离。结果，转子上的总压力上升急剧下降。结果表明，泄漏涡破裂的影响可以导致压气机转子的失速。