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Research Papers

Mach Number Distribution and Profile Losses for Low-Pressure Turbine Profiles With High Diffusion Factors

[+] Author and Article Information
Roland Brachmanski

Institute of Jet Propulsion,
Universität der Bundeswehr München,
Neubiberg 85577, Germany
e-mail: roland.brachmanski@unibw.de

Reinhard Niehuis

Institute of Jet Propulsion,
Universität der Bundeswehr München,
Neubiberg 85577, Germany
e-mail: reinhard.niehuis@unibw.de

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received August 7, 2016; final manuscript received March 5, 2017; published online May 9, 2017. Assoc. Editor: Guillermo Paniagua.

J. Turbomach 139(10), 101002 (May 09, 2017) (10 pages) Paper No: TURBO-16-1187; doi: 10.1115/1.4036436 History: Received August 07, 2016; Revised March 05, 2017

The results of this investigation come from two linear cascades at high diffusion factors (DFs). The measurements presented for each low-pressure turbine (LPT) profile were conducted at midspan under a range of Reynolds- and exit Mach numbers. The exit Mach number was varied in a range covering low subsonic up to values where a transonic flow regime on the suction side of the blade could be expected. This work focuses on two profiles with a diffusion factor in a range of 0.18DF0.22, where values in this range are considered as a comparable for the two cascades. Profile A is a front-loaded design and has shown no obvious flow separation on the suction side of the blade. Compared to the design A, design B is a more aft-loaded profile which exhibits flow separation on the suction side for all Reynolds numbers investigated. The integral total pressure losses were evaluated by wake traverses downstream of the airfoil. To determine the isentropic Mach numbers and the character of the boundary layer along the suction side of the profile, the static pressure measurements and traverses with a flattened Pitot probe were carried out. A correlation between the position of maximum Mach number on the suction side and the integral total pressure losses has been successfully established. The results show that the optimum location of peak Mach number to minimize integral total pressure losses is significantly dependent on the Reynolds number. However, the correlation presented in this paper, which is based on the data of the integral total pressure losses of an attached boundary layer, is not able to predict the integral total pressure loss or the location of the maximum Mach number on the suction side of the blade when an open separation bubble occurs.

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References

Wisler, D. , 1998, “ The Technical and Economic Relevance of Understanding Boundary Layer Transition in Gas Turbine Engines,” Minnobrook II 1997 Workshop on Boundary Layer Transition in Turbomachines, NASA Lewis Research Center, Cleveland, OH, Technical Report No. NASA/CP-1998-206958.
Praisner, T. J. , Grover, E. A. , Knezevici, D. C. , Popovic, I. , Sjolander, S. A. , Clarke, J. P. , and Sondergaard, R. , 2013, “ Towards the Expansion of Low-Pressure-Turbine Airfoil Design Space,” ASME J. Turbomach., 135(6), p. 061007. [CrossRef]
Denton, J. , 1993, “ Loss Mechanisms in Turbomachines,” ASME J. Turbomach., 115(4), pp. 621–656. [CrossRef]
Banieghbal, M. R. , Curtis, E. M. , Denton, J. D. , Hodson, H. P. , Huntsman, I. , and Schulte, V. S. , 1995, “ Wake Passing in LP Turbines,” AGARD Conference Loss Mechanisms and Unsteady Flows in Turbomachines, Derby, UK, May 8–12, Paper No. 23.
Curtis, E. M. , Hodson, H. P. , Banieghbal, M. R. , Howell, R. J. , and Harvey, N. W. , 1997, “ Development of Blade Profiles for Low-Pressure Turbine Applications,” ASME J. Turbomach., 119(3), pp. 531–538. [CrossRef]
Gier, J. , Franke, M. , Huebner, N. , and Schroeder, T. , 2008, “ Designing LP Turbines for Optimized Airfoil Lift,” ASME Paper No. GT-2008-51101.
Coull, J. , Thomas, R. , and Hodson, H. , 2010, “ Velocity Distributions for Low Pressure Turbines,” ASME J. Turbomach., 132(4), p. 041006. [CrossRef]
Coull, J. , and Hodson, H. , 2012, “ Blade Loading and Its Application in the Mean-Line Design of Low Pressure Turbines,” ASME J. Turbomach., 135(2), p. 021032. [CrossRef]
Wakelam, C. T. , Niehuis, R. , and Hoeger, M. , 2013, “ A Comparison of Three Low Pressure Turbine Designs,” ASME J. Turbomach., 135(5), p. 051026. [CrossRef]
Kiock, R. , Laskowski, G. , and Hoheisel, H. , 1982, Die Erzeugung Höherer Turbulenzgrade in der Messstrecke des Hochgeschwindigkeits-Gitterwindkanals in Braunschweig zur Simulation Turbomaschinenähnlicher Bedingungen Forschungsbericht, Institut für Entwurfsaerodynamik, Braunschweig, Germany.
Sturm, W. , and Fottner, L. , 1985, “ The High Speed Cascade Wind Tunnel of the German Armed Forces University Munich,” Eighth Symposium on Measurement Techniques for Transonic and Supersonic Flow in Cascades and Turbomachines, Genova, Italy, Oct. 24–25.
Mayle, R. E. , 1991, “ The 1991 IGTI Scholar Lecture: The Role of Laminar-Turbulent Transition in Gas Turbine Engines,” ASME J. Turbomach., 113(4), pp. 509–537. [CrossRef]
Butler, R. J. , Byerley, A. R. , Van Treuen, K. , and Baughn, J. , 2001, “ The Effect of Turbulence Intensity and Length Scale on Low-Pressure Turbine Blade Aerodynamics,” Int. J. Heat Fluid Flow, 22(2), pp. 123–133. [CrossRef]
Gomes, R. , 2010, “ On Aerothermal Effects of Film Cooling on Turbine Blades With Flow Separation,” Ph.D. dissertation, Fakultät für Luft- und Raumfahrttechnik, Universität der Bundeswehr München, Neubiberg, Germany.
Amecke, J. , 1967, “ Auswertung von Nachlaufmessungen an Ebenen Schaufelgittern,” AVA Göttingen, Messbericht No. 67 A 49.
Nitsche, W. , and Brunn, A. , 2006, Strömungsmesstechnik, Springer-Verlag, Berlin.
Schlichting, H. , 1964, Grenzschichttheorie 5. Überarbeitete Auflage, G. Braun , ed., Springer-Verlag, Berlin.
Hoeger, M. , 1992, “ Theoretische und Experimentelle Untersuchungen an Schaufelprofilen mit Grenzschichtumschlag Über Eine Laminare Ablöseblase,” Ph.D. dissertation, Technische Universität Braunschweig, Braunschweig, Germany.
Stotz, S. , Wakelam, C. T. , Niehuis, R. , and Guendogdu, Y. , 2014, “ Investigation of the Suction Side Boundary Layer Development on Low Pressure Turbine Airfoils With and Without Separation Using a Preston Probe,” ASME Paper No. GT2014-25908.
Young, A. D. , and Maas, J. N. , 1937, “ The Behavior of a Pitot Tube in a Transverse Total Pressure Gradient,” Aeronautical Resources Council, London, Report No. 1770.
Brachmanski, R. , Niehuis, R. , and Bosco, A. , 2014, “ Investigation of a Separated Boundary Layer and Its Influence on Secondary Flow of a Transonic Turbine Profile,” ASME Paper No. GT2014-25890.
Wilcox, D. C. , 1998, Turbulence Modelling for CFD, 2nd ed., DCW Industries, Anaheim, CA.
Ciorciari, R. , Kirik, I. , and Niehuis, R. , 2014, “ Effects of Unsteady Wakes on the Secondary Flows in the Linear T106 Turbine Cascade,” ASME J. Turbomach., 136(9), p. 091010. [CrossRef]
Menter, F. , Langtry, R. , Likki, S. , Suzen, Y. B. , Huang, P. , and Völker, S. , 2006, “ A Correlation-Based Transition Model Using Local Variables—Part 1: Model Formulation,” ASME J. Turbomach., 128(3), pp. 413–422. [CrossRef]
Langtry, R. , Menter, F. , Likki, S. , Suzen, Y. B. , Huang, P. , and Völker, S. , 2004, “ A Correlation-Based Transition Model Using Local Variables—Part 2: Test Cases and Industrial Applications,” ASME J. Turbomach., 128(3), pp. 423–434.
Abu-Ghannam, B. , and Shaw, R. , 1980, “ Natural Transition of Boundary Layers—The Effects of Turbulence, Pressure Gradient, and Flow History,” J. Mech. Eng. Sci., 22(5), pp. 213–228. [CrossRef]
Coull, J. , and Hodson, H. , 2012, “ Predicting the Profile Loss of High-Lift Low Pressure Turbines,” ASME J. Turbomach., 134(2), p. 021002. [CrossRef]
Hourmouziadis, J. , 1989, “ Aerodynamic Design of Low-Pressure Turbines,” AGARD Lect. Ser., 167, pp. 8.1–8.40.
Hoheisel, H. , Kiock, R. , Lichtfuß, H. J. , and Fottner, L. , 1987, “ Influence of Free-Stream Turbulence and Blade Pressure Gradient on Boundary Layer and Loss Behavior of Turbine Cascades,” ASME J. Turbomach., 109(2), pp. 210–219. [CrossRef]
Mayle, R. , and Schulz, A. , 1997, “ Heat Transfer Committee and Turbomachinery Committee Best Paper of 1996 Award: The Path to Predicting Bypass Transition,” ASME J. Turbomach., 119(3), pp. 405–411. [CrossRef]
Martinstetter, M. , 2010, “ Experimentelle Untersuchungen zur Aerodynamik Hoch Belasteter Niederdruckturbinen-Beschaufelungen,” Ph.D. dissertation, Fakultät für Luft- und Raumfahrttechnik, Universität der Bundeswehr München, Neubiberg, Germany.
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]

Figures

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Fig. 1

The high-speed cascade wind tunnel

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Fig. 2

Schematic of the cascade co-ordinate system (geometry not to scale)

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Fig. 3

Mach number distribution of profile B

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Fig. 4

Mach number distribution of profile A

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Fig. 5

Wake traverses of profile B

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Fig. 6

Wake traverses of profile A

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Fig. 7

Integral total pressure losses as a function of maximum Mach number location

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Fig. 8

Derivatives of the parabola

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Fig. 9

Integral total pressure losses as a function of maximumMach number location for high DF and variation of Tu intensities

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Fig. 10

Mach number distribution of profile B at Re2th=125,000 and variation of Tu intensities

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Fig. 11

Wake traverses of profile B at Re2th=125,000 for different Tu intensities

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Fig. 12

Dynamic pressure distribution of design B at Re2th=125,000 and with variation of Tu intensities

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Fig. 13

Trailing edge profiles of design B at Re2th=125,000 and with variation of Tu intensities

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Fig. 14

Mach number distributions of the profile B at Re2th=125,000 at high Tu intensities

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Fig. 15

Mach number distributions of the profile B at Re2th=125,000 at low Tu intensities

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Fig. 16

Friction factors of design B at Re2th=125,000 and variation of Tu intensities

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