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

Ken Ichi Funazaki, Kazutoyo Yamada, Yasuhiro Chiba, Nozomi Tanaka

研究成果: Chapter in Book/Report/Conference proceedingConference contribution

10 被引用数 (Scopus)

抄録

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.

本文言語英語
ホスト出版物のタイトル2008 Proceedings of the ASME Turbo Expo
ホスト出版物のサブタイトルPower for Land, Sea, and Air
PART B
DOI
出版ステータス出版済み - 2008
イベント2008 ASME Turbo Expo - Berlin, ドイツ
継続期間: 6 9 20086 13 2008

出版物シリーズ

名前Proceedings of the ASME Turbo Expo
番号PART B
6

その他

その他2008 ASME Turbo Expo
Countryドイツ
CityBerlin
Period6/9/086/13/08

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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