Numerical and Experimental Studies on Separated Boundary Layers over Ultra-High Lift Low-Pressure Turbine Cascade Airfoils with Variable Solidity: Effects of Free-stream Turbulence
Numerical and Experimental Studies on Separated Boundary Layers over Ultra-High Lift Low-Pressure Turbine Cascade Airfoils with Variable Solidity: Effects of Free-stream Turbulence
复制标题
DOI：
10.1115/gt2008-50718
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Funazaki;Kazutoyo Yamada;Y. Chiba;N. Tanaka
中科院分区：
文献类型：
--
作者：
K. Funazaki;Kazutoyo Yamada;Y. Chiba;N. Tanaka
本文涉及 LES 研究和测量，涉及超高升力低压涡轮机翼上入口自由流湍流与带有分离气泡的边界层之间的相互作用。测试翼型的横截面是民用航空发动机高负载低压涡轮的典型横截面。通过将翼型螺距增加至少 25%，同时保持叶片间通道中的喉部，可以降低叶栅的坚固性。根据弦长和平均出口速度，检查的雷诺数为 57,000。自由流湍流约为 0.85%（无网格条件）和 2.1%（有网格条件）。对边界层进行热线探针测量，以获得自由流湍流影响下边界层的时间平均和时间分辨特性。新开发的探头定位工具安装在叶栅下游，堵塞最小，可沿垂直于翼型表面的线进行精确的探头定位。执行基于高分辨率 LES（大涡模拟）的数值分析，以增强对超高升力和高升力低压涡轮机翼型周围流场的理解。重点研究了分离气泡剪切层的固有不稳定性与自由流湍流的关系。标准 Smagorinsky 模型用于亚网格尺度建模。使用的流动求解器是内部代码，最初由作者之一开发为基于 FVM（有限体积法）的完全隐式且时间精确的雷诺平均纳维斯托克斯代码。本研究采用冯卡门-鲍湍流能谱通过 SNGR（随机噪声生成和辐射）方法创建的均质各向同性湍流，用于模拟入口湍流。版权所有 © 2008 ASME
This paper deals with LES investigation, along with measurements, on the interaction between inlet freestream turbulence and boundary layers with separation bubble over ultra-high lift low-pressure turbine airfoils. The cross section of the test airfoils is typical for highly-loaded LP turbines for civil aeroengines. The solidity of the cascade can be reduced by increasing the airfoil pitch by at least 25%, while maintaining the throat in the blade-to-blade passage. Reynolds number examined is 57,000, based on chord length and averaged exit velocity. Free-stream turbulence is about 0.85% (no grid condition) and 2.1% (with grid condition). Hot-wire probe measurements of the boundary layer are carried out to obtain time-averaged and time-resolved characteristics of the boundary layers under the influence of the freestream turbulence. A newly developed probe positioning tool, which is installed downstream of the cascade with minimal blockage, enables precise probe positioning along lines normal to the airfoil surface. Numerical analysis based on high-resolution LES (Large-Eddy Simulation) is executed to enhance the understanding of the flow field around the Ultra-High Lift and High Lift LP turbine airfoils. Emphasis is placed on the relationship of inherent instability of the shear layer of the separation bubble and the free-stream turbulence. Standard Smagorinsky model is employed for subgrid scale modeling. The flow solver used is an in-house code that was originally developed by one of the authors as FVM (Finite Volume Method)-based fully implicit and time-accurate Reynolds-Averaged Navier-Stokes code. Homogeneous isotropic turbulence created with SNGR (Stochastic Noise Generation and Radiation) method using von Karman-Pao turbulent energy spectrum is applied in the present study for the emulation of inlet turbulence.Copyright © 2008 by ASME