Unsteady Boundary Layer Transition on a High Pressure Turbine Rotor Blade
Unsteady Boundary Layer Transition on a High Pressure Turbine Rotor Blade
复制标题
高压涡轮转子叶片上的非稳态边界层转变
DOI：
10.1115/99-gt-194
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发表时间：
1999
影响因子：
4
通讯作者：
F. Kost
中科院分区：
文献类型：
--
作者：
M. Tiedemann;F. Kost
这项研究的目的是通过实验确定高压涡轮转子叶片边界层层流到湍流转变过程的位置、范围和模式。结果基于时间分辨的定性壁剪切应力数据，该数据源自表面热膜测量。测试是在哥廷根 DLR 的“旋转叶栅风洞”中进行的。为了评估经过的尾流和冲击对非定常边界层转变的影响，除了全级试验之外，还进行了未扰动转子入口流的试验。两种不同的过渡模式导致吸力侧出现周期性不稳定、多模态的过渡。在两次唤醒之间，过渡以旁路模式开始，并以分离流过渡结束。在尾流下方，发生了简单的旁路转换。压力侧的弱周期性边界层特征表明该表面并未受到经过的尾流或冲击的显着影响。获取的数据表明，周期性扰动的吸力侧边界层比未扰动的流场更不易破裂。因此，这些叶片可能承受更高的空气动力载荷。因此，与低压涡轮机一样，高压涡轮机中的不稳定效应可以允许相对于原始设计减少转子叶片的数量
This investigation is aimed at the experimental determination of the location, the extent, and the modes of the laminar-to-turbulent transition processes in the boundary layers of a high pressure turbine rotor blade. The results are based on time-resolved, qualitative wall shear stress data which was derived from surface hotfilm measurements. The tests were conducted in the "Windtunnel for Rotating Cascades" of the DLR in Gottingen. For the evaluation of the influence of passing wakes and shocks on the unsteady boundary layer transition, a test with undisturbed rotor inlet flow was conducted in addition to full stage tests. Two different transition modes led to a periodic-unsteady, multimoded transition on the suction side. In between two wakes, transition started in the bypass mode and terminated as separated-flow transition. Underneath the wakes, plain bypass transition occurred. The weak periodic boundary layer features on the pressure side indicate that this surface was not significantly affected by passing wakes or shocks. The acquired data reveals that the periodically disturbed suction side boundary layer is less susceptible to bubble bursting than the undisturbed flowfield. Thus, these blades may be subjected to higher aerodynamic loads. Accordingly, as in low pressure turbines, the unsteady effects in high pressure turbines may allow for a reduction of the number of rotor blades, with respect to the original design