Research Papers

Off-Design Performance of a Highly Loaded Low Pressure Turbine Cascade Under Steady and Unsteady Incoming Flow Conditions

[+] Author and Article Information
Daniele Simoni

DIME—Università di Genova,
Via Montallegro 1,
Genova I-16145, Italy
e-mail: daniele.simoni@unige.it

Marco Berrino

DIME—Università di Genova,
Via Montallegro 1,
Genova I-16145, Italy
e-mail: marco.berrino@unige.it

Marina Ubaldi

DIME—Università di Genova,
Via Montallegro 1,
Genova I-16145, Italy
e-mail: marina.ubaldi@unige.it

Pietro Zunino

DIME—Università di Genova,
Via Montallegro 1,
Genova I-16145, Italy
e-mail: pietro.zunino@unige.it

Francesco Bertini

AvioAero R&D,
V. I Maggio,
Rivalta (TO) 99 I-10040, Italy
e-mail: francesco.bertini@avioaero.com

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received October 27, 2014; final manuscript received November 4, 2014; published online January 7, 2015. Editor: Ronald S. Bunker.

J. Turbomach 137(7), 071009 (Jul 01, 2015) (9 pages) Paper No: TURBO-14-1280; doi: 10.1115/1.4029200 History: Received October 27, 2014; Revised November 04, 2014; Online January 07, 2015

The off-design performance of a highly loaded low pressure (LP) turbine cascade has been experimentally investigated, at the Aerodynamics and Turbomachinery Laboratory of Genova University, under steady and unsteady incoming flow conditions. Tests have been performed for different Reynolds numbers (Re = 70,000 and Re = 300,000), in order to cover the typical LP turbine working range. The incidence angle has been varied between i = −9 deg and +9 deg, in order to test off-design conditions characterizing the engine. For the unsteady case, upstream wake periodic perturbations have been generated by means of a tangential wheel of radial rods. The cascade and the moving bars system have been located over a common bearing in order to make them rigidly rotating. This solution allows a proper comparison of the cascade robustness at the incidence angle variation under steady and unsteady incoming flows, since all the other operating parameters have been kept the same. In order to survey the variation of the unsteady boundary conditions characterizing the off-design operation of the downstream cascade, time-mean and time-resolved wake structures have been analyzed in detail. For what concerns the cascade performance, profile aerodynamic loadings and total pressure loss coefficients at the cascade exit have been surveyed for the different incidence angles under both steady and unsteady inflows. Different total pressure loss sensitivity at the incidence angle variation has been observed for the steady and the unsteady inflow conditions. Hot-wire anemometer has been employed to obtain the time-mean pressure and suction side boundary layer velocity profiles at the blade trailing edge for the different conditions. The integral parameters at the cascade exit plane help to justify the different loss trend versus incidence angle found for the steady and the unsteady cases, explaining the different sensibility of the blade profile when this operates under realistic unsteady inflow condition.

Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.


Zhang, X. F., Vera, M., Hodson, H., and Harvey, N., 2006, “Separation and Transition Control in an Aft-Loaded Ultra-High-Lift LP Turbine Blade at Low Reynolds Number: Low Speed Investigation,” ASME J. Turbomach., 128(3), pp. 517–527. [CrossRef]
Lazaro, B. J., Gonzalez, E., and Vazquez, R., 2008, “Unsteady Loss Production Mechanisms in Low Reynolds Number, High Lift, Low Pressure Turbine Profiles,” ASME Paper No. GT2007-28142. [CrossRef]
Volino, R. J., 2002, “Separated Flow Transition Under Simulated Low-Pressure Turbine Airfoil Conditions—Part 1: Mean Flow and Turbulence Statistics,” ASME J. Turbomach., 124(4), pp. 645–655. [CrossRef]
Bons, J. P., Pluim, J., Gompertz, K., Bloxham, M., and Clark, J. P., 2012, “The Application of Flow Control to an Aft-Loaded Low Pressure Turbine Cascade With Unsteady Wakes,” ASME J. Turbomach., 134(3), p. 031009. [CrossRef]
Simoni, D., Ubaldi, M., Zunino, P., Lengani, D., and Bertini, F., 2012, “An Experimental Investigation of the Separated-Flow Transition Under High-Lift Turbine Blade Pressure Gradients,” Flow Turbul. Combust., 88(1–2), pp. 45–62. [CrossRef]
Simoni, D., Ubaldi, M., and Zunino, P., 2012, “Loss Production Mechanisms in a Laminar Separation Bubble,” Flow Turbul. Combust., 89(4), pp. 547–562. [CrossRef]
Lou, W., and Hourmouziadis, J., 2000, “Separation Bubbles Under Steady and Periodic-Unsteady Main Flow Conditions,” ASME J. Turbomach., 122(4), pp. 634–643. [CrossRef]
Halstead, D. E., Wisler, D. C., Okiishi, T., Walker, G. J., Hodson, H. P., and Shin, H. W., 1997, “Boundary Layer Development in Axial Compressor and Turbines: Part 1 of 4—Composite Picture,” ASME J. Turbomach., 119(1), pp. 114–127. [CrossRef]
Mailach, R., and Vogeler, K., 2004, “Aerodynamic Blade Row Interaction in an Axial Compressor—Part I: Unsteady Boundary Layer Development,” ASME J. Turbomach., 126(1), pp. 35–44. [CrossRef]
Gompertz, K. A., and Bons, J. P., 2011, “Combined Unsteady Wakes and Active Flow Control on a Low-Pressure Turbine Airfoil,” AIAA J. Propul. Power, 27(5), pp. 990–1000. [CrossRef]
Simoni, D., Ubaldi, M., and Zunino, P., 2013, “Experimental Investigation of the Interaction Between Incoming Wakes and Instability Mechanisms in a Laminar Separation Bubble,” Exp. Therm. Flow Sci., 50, pp. 54–60. [CrossRef]
Stadtmuller, P., Fottner, L., and Fiala, A., 2000, “Experimental and Numerical Investigation of Wake-Induced Transition on a Highly Loaded LP Turbine at Low Reynolds Numbers,” ASME Paper No. GT2000-0269. [CrossRef]
Hodson, H. P., and Howell, R. J., 2005, “The Role of Transition in High-Lift Low-Pressure Turbines for Aeroengines,” Prog. Aerosp. Sci., 41(6), pp. 419–454. [CrossRef]
Simoni, D., Ubaldi, M., Zunino, P., and Bertini, F., 2012, “Transition Mechanisms in Laminar Separation Bubbles With and Without Incoming Wakes and Synthetic Jet Effects,” Exp. Fluids, 53(1), pp. 173–186. [CrossRef]
Cattanei, A., Zunino, P., Schröder, T., Stoffel, B., and Matyschok, B., 2006, “Detailed Analysis of Experimental Investigations on Boundary Layer Transition in Wake Disturbed Flow,” ASME Paper No. GT2006-90128. [CrossRef]
Canepa, E., Formosa, P., Lengani, D., Simoni, D., Ubaldi, M., and Zunino, P., 2007, “Influence of Aerodynamic Loading on Rotor-Stator Aerodynamic Interaction in a Two-Stage Low Pressure Research Turbine,” ASME J. Turbomach., 129(4), pp. 765–772. [CrossRef]
Houtermans, R., Coton, T., and Arts, T., 2004, “Aerodynamic Performance of a Very High Lift Low Pressure Turbine Blade With Emphasis on Separation Prediction,” ASME J. Turbomach., 126(3), pp. 406–413. [CrossRef]
Zoric, T., Popovic, I., Sjolander, S. A., Praisner, T., and Grover, E., 2007, “Comparative Investigation of Three Higly Loaded LP Turbine Airfoils: Part II—Measured Profile and Secondary Losses at Off-Design Incidence,” ASME Paper No. GT2007-27538. [CrossRef]
Schlichting, H., 1979, Boundary Layer Theory, McGraw-Hill, New York.
Boutilier, M. S. H., and Yarusevych, S., 2012, “Parametric Study of Separation and Transition Characteristics Over an Airfoil at Low Reynolds Numbers,” Exp. Fluids, 52(6), pp. 1491–1506. [CrossRef]
Satta, F., Simoni, D., Ubaldi, M., Zunino, P., and Bertini, F., 2014, “Loading Distribution Effects on Separated Flow Transition of Ultra-High-Lift Turbine Blades: Steady and Unsteady Inflows,” AIAA J. Propul. Power, 30(3), pp. 845–856 [CrossRef]
Vera, M., and Hodson, H., 2002, “Low Speed vs High Speed Testing of LP Turbine Blade-Wake,” The 16th Symposium on Measuring Techniques in Transonic and Supersonic Flow in Cascades and Turbomachines, Cambridge, pp. 1–10.


Grahic Jump Location
Fig. 2

Wake velocity and turbulence profiles at nominal incidence i = 0 deg

Grahic Jump Location
Fig. 3

Comparison of wake velocity and turbulence profiles at different incidences

Grahic Jump Location
Fig. 4

Aerodynamic loading distributions: comparison between steady and unsteady cases

Grahic Jump Location
Fig. 7

Suction side velocity profiles at the blade trailing edge, Re = 70,000

Grahic Jump Location
Fig. 8

Boundary layer integral parameters: steady inflow, Re = 70,000

Grahic Jump Location
Fig. 9

Boundary layer integral parameters: unsteady inflow, Re = 70,000

Grahic Jump Location
Fig. 5

Aerodynamic loading distributions: steady case, Re = 70,000

Grahic Jump Location
Fig. 6

Aerodynamic loading distributions: unsteady case, Re = 70,000

Grahic Jump Location
Fig. 10

Dimensionless total pressure loss coefficient distributions

Grahic Jump Location
Fig. 11

Control volume for the moving bars system

Grahic Jump Location
Fig. 12

Angle variation (top) and total pressure drop (bottom) across the moving bars system



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In