Modeling Vortex Generating Jet-Induced Transition in Low-Pressure Turbines

The current design of low-pressure turbines (LPTs) with steady-blowing vortex generating jets (VGJs) uses steady computational fluid dynamics (CFD). The present work aims to support this design approach by proposing a new semiempirical transition model for injection-induced laminar-turbulent boundary layer transition. It is based on the detection of cross-flow vortices in the boundary layer which cause inflectional cross-flow velocity profiles. The model is implemented in the CFD code TRACE within the framework of the γ-Reθ transition model and is a reformulated, recalibrated, and extended version of a previously presented model. It is extensively validated by means of VGJ as well as non-VGJ test cases capturing the local transition process in a physically reasonable way. Quantitative aerodynamic design parameters of several VGJ configurations including steady and periodic-unsteady inflow conditions are predicted in good accordance with experimental values. Furthermore, the quantitative prediction of end-wall flows of LPTs is improved by detecting typical secondary flow structures. For the first time, the newly derived model allows the quantitative design and optimization of LPTs with VGJs.

[1]  R. Volino,et al.  Experimental and Computational Investigations of Low-Pressure Turbine Separation Control Using Vortex Generator Jets , 2009 .

[2]  Howard P. Hodson,et al.  Separation and Transition Control on an Aft-Loaded Ultra-High-Lift LP Turbine Blade at Low Reynolds Numbers: Low-Speed Investigation , 2006 .

[3]  Heinz-Peter Schiffer,et al.  The Application of Ultra High Lift Blading in the BR715 LP Turbine , 2001 .

[4]  W. Saric,et al.  STABILITY AND TRANSITION OF THREE-DIMENSIONAL BOUNDARY LAYERS , 2003 .

[5]  Wolfgang Rodi,et al.  The Influence of Density Difference Between Hot and Coolant Gas on Film Cooling by a Row of Holes: Predictions and Experiments , 1992 .

[6]  Hong Yang,et al.  Numerical Investigation of Casing Treatment Mechanisms With a Conservative Mixed-Cell Approach , 2003 .

[7]  R. E. Mayle,et al.  The 1991 IGTI Scholar Lecture: The Role of Laminar-Turbulent Transition in Gas Turbine Engines , 1991 .

[8]  Howard P. Hodson,et al.  Endwall Boundary Layer Development in an Engine Representative Four-Stage Low Pressure Turbine Rig , 2009 .

[9]  Hualing Luo,et al.  Passive control of laminar separation bubble with spanwise groove on a low-speed highly loaded low-pressure turbine blade , 2009 .

[10]  Yasuaki Kohama,et al.  A New Parameter for Predicting Crossflow Instability , 1991 .

[11]  Konrad Vogeler,et al.  Reduction of secondary flow losses in turbine cascades by leading edge modifications at the endwall , 2001 .

[12]  Miguel R. Visbal,et al.  Numerical Investigation of Plasma-Based Flow Control for Transitional Highly-Loaded Low-Pressure Turbine , 2007 .

[13]  Matthias Franke,et al.  Passive Boundary Layer Control on a Highly Loaded Low Pressure Turbine Cascade , 2010 .

[14]  James P. Johnston,et al.  Streamwise vortex production by pitched and skewed jets in a turbulent boundary layer , 1991 .

[15]  Ralph J. Volino Separation Control on Low-Pressure Turbine Airfoils Using Synthetic Vortex Generator Jets , 2003 .

[16]  Dragan Kozulovic Application of a Multimode Transition Model to Turbomachinery Flows , 2007 .

[17]  G. Ingram,et al.  Time Resolved Measurements in the Durham Cascade , 2011 .

[18]  R. Rivir,et al.  A PIV Study of a Plasma Discharge Flow-Control Actuator on a Flat Plate in an Aggressive Pressure Induced Separation , 2006 .

[19]  Florian R. Menter,et al.  Correlation-Based Transition Modeling for Unstructured Parallelized Computational Fluid Dynamics Codes , 2009 .

[20]  Richard J. Margason,et al.  Fifty Years of Jet in Cross Flow Research , 1993 .

[21]  Vijay K. Garg Low-Pressure Turbine Separation Control— Comparison With Experimental Data , 2002 .

[22]  Thomas Röber,et al.  Modelling the Streamline Curvature Effects in Turbomachinery Flows , 2006 .

[23]  P. Moin,et al.  Eddies, streams, and convergence zones in turbulent flows , 1988 .

[24]  Michael Henke,et al.  Unsteady Wake-Blade Interaction: A Correlation Between Surface Pressure Fluctuations and Loss Generation , 2012 .

[25]  D. G. Gregory-Smith,et al.  Transition Effects on Secondary Flows in a Turbine Cascade , 1996 .

[26]  J. Bons,et al.  Control of Low-Pressure Turbine Separation Using Vortex-Generator Jets , 2002 .

[27]  L. Langston,et al.  Secondary Flows in Axial Turbines—A Review , 2001, Annals of the New York Academy of Sciences.

[28]  Dirk Nürnberger,et al.  Influence of Blade Fillets on the Performance of a 15 stage Gas Turbine Compressor , 2008 .

[29]  Yasuaki Kohama,et al.  Some expectation on the mechanism of cross-flow instability in a swept wing flow , 1987 .

[30]  P. Roe Approximate Riemann Solvers, Parameter Vectors, and Difference Schemes , 1997 .

[31]  Ralph J. Volino Passive Flow Control on Low-Pressure Turbine Airfoils , 2003 .

[32]  D. Wilcox Reassessment of the scale-determining equation for advanced turbulence models , 1988 .

[33]  James H. Leylek,et al.  A detailed analysis of film-cooling physics: Part II -- Compound-angle injection with cylindrical holes , 2000 .

[34]  Joerg R. Seume,et al.  Transition Modelling for Vortex Generating Jets on Low-Pressure Turbine Profiles , 2011 .

[35]  John D. Denton,et al.  The 1993 IGTI Scholar Lecture: Loss Mechanisms in Turbomachines , 1993 .

[36]  C. H. Sieverding,et al.  Investigation of the Effectiveness of Various Types of Boundary Layer Transition Elements of Low Reynolds Number Turbine Bladings , 2004 .

[37]  Jochen Gier,et al.  Designing Low Pressure Turbines for Optimized Airfoil Lift , 2010 .

[38]  Mounir B. Ibrahim,et al.  LES Flow Control Simulations for Highly Loaded Low Pressure Turbine Airfoil (L1A) Using Pulsed Vortex Generator Jets , 2010 .

[39]  Matthias Franke,et al.  PREDICTING TRANSITION ON LOW-PRESSURE TURBINE PROFILES , 2010 .