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在低压涡轮内部上游周期性扫过的尾迹是下游叶片排内最重要的非定常扰动源,会对边界层的失稳和转捩过程产生决定性的影响.在施加低压涡轮负荷分布的平板上,采用热线对雷诺数为130 000工况下,有/无尾迹作用时分离剪切层中的速度波动进行了测量.通过对比两种工况下分离剪切层中的扰动发展,分析了尾迹对分离泡稳定性的影响.结果表明:在无尾迹来流工况下,扰动在分离泡前部的增长符合线性不稳定机制,扰动增长至饱和后非线性机制开始起作用.主导分离剪切层的失稳过程的为K-H(Kelvin-Helmholtz)无黏不稳定机制.尾迹与分离剪切层的相互作用产生的扰动的增长在分离泡前部同样满足线性不稳定机制.尾迹加速了分离剪切层的失稳转捩进程,从而抑制了分离.
The wake swept periodically upstream in the low-pressure turbine is the most important unsteady disturbance source in the downstream vane row, which will have a decisive influence on the instability and transition of the boundary layer.In the plate with low-pressure turbine load distribution, The hot-line is used to measure the velocity fluctuation in the separation shear layer with / without wake function under the Reynolds number of 130 000. By comparing the disturbance development in the separation shear layer under the two conditions, the wake pairs The results show that under the condition of no-wake flow, the increase of disturbance in the front of the bubble agrees with the linear instability mechanism, and the nonlinear mechanism begins to play a role when the disturbance increases to saturation. The instability of KH (Kelvin-Helmholtz) is the non-viscous instability mechanism. The increase of the disturbance caused by the interaction between the wake and the separation shear layer also satisfies the linear instability mechanism in the front of the separation bubble.The wake accelerates the separation shear Stratospheric instability transition process, thereby inhibiting the separation.