0
Research Papers

Unsteady Rotor Hub Passage Vortex Behavior in the Presence of Purge Flow in an Axial Low Pressure Turbine

[+] Author and Article Information
P. Jenny

e-mail: jenny@lec.mavt.ethz.ch

R. S. Abhari

Laboratory for Energy Conversion,
Department of Mechanical and Process Engineering,
ETH Zurich, 8092
Zurich, Switzerland

M. G. Rose

Institute of Aeronautical Propulsion,
University of Stuttgart,
70569 Stuttgart, Germany

J. Gier

MTU Aero Engines GmbH,
Dachauer Strasse 665,
80995 Munich, Germany

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received August 7, 2012; final manuscript received August 31, 2012; published online June 28, 2013. Editor: David Wisler.

J. Turbomach 135(5), 051022 (Jun 28, 2013) (9 pages) Paper No: TURBO-12-1167; doi: 10.1115/1.4007837 History: Received August 07, 2012; Revised August 31, 2012

The paper presents an experimental and computational study of the unsteady behavior of the rotor hub passage vortex in an axial low-pressure turbine. Different flow structures are identified as having an effect on the size, strength, shape, position, and the unsteady behavior of the rotor hub passage vortex. The aim of the presented study is to analyze and quantify the sensitivities of the different flow structures and to investigate their combined effects on the rotor hub passage vortex. Particular attention is paid to the effect of the rim seal purge flow and of the unsteady blade row interaction. The rotor under investigation has nonaxisymmetric end walls on both hub and shroud and is tested at three different rim seal purge flow injection rates. The rotor has separated pressure sides at the operating point under investigation. The nondimensional parameters of the tested turbine match real engine conditions. The 2-sensor fast response aerodynamic probe (FRAP) technique and the fast response entropy probe (FENT) systems developed by ETH Zurich are used in this experimental campaign. Time-resolved measurements of the unsteady pressure, temperature and entropy fields between the rotor and stator blade rows are taken and analyzed. Furthermore, the results of URANS simulations are compared to the measurements and the computations are also used to detail the flow field. The experimental results show a 30% increase of the maximum unsteadiness and a 4% increase of the loss in the hub passage vortex per percent of injected rim seal cooling flow. Compared to a free stream particle, the rim seal purge flow was found to do 60% less work on the rotor.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Kobayashi, N., Matsumato, M., and Shizuya, M., 1984, “An Experimental Investigation of a Gas-Turbine Disk Cooling System,” ASME J. Eng. Gas Turbines Power, 106(1), pp. 136–141. [CrossRef]
Chew, J. W., Dadkhah, S., and Turner, A. B., 1992, “Rim Sealing of Rotor-Stator Wheelspaces in the Absence of External Flow,” ASME J. Turbomach., 114(2), pp. 433-438. [CrossRef]
Dadkhah, S., Turner, A. B., and Chew, J. W., 1992, “Performance of Radial Clearance Rim Seals in Upstream and Downstream Rotor-Stator Wheelspaces,” ASME J. Turbomach., 114(2), pp. 439–445. [CrossRef]
McLean, C., Camci, C., and Glezer, B., 2001, “Mainstream Aerodynamic Effects Due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part II—Aerodynamic Measurements in the Rotational Frame,” ASME J. Turbomach., 123(4), pp. 697–703. [CrossRef]
Ong, J. H. P., Miller, R. J., and Uchida, S., 2006, “The Effect of Coolant Injection on the Endwall Flow of a High Pressure Turbine,” ASME Turbo Expo, Barcelona, Spain, May 8–11, ASME Paper No. GT2006-91060. [CrossRef]
Paniagua, G., Denos, R., and Almeida, S., 2004, “Effect of the Hub Endwall Cavity Flow on the Flow-Field of a Transonic High-Pressure Turbine,” ASME J. Turbomach., 126(4), pp. 578–586. [CrossRef]
Reid, K., Denton, J., Pullan, G., Curtis, E., and Longley, J., 2006, “The Effect of Stator–Rotor Hub Sealing Flow on the Mainstream Aerodynamics of a Turbine,” ASME Turbo Expo, Barcelona, Spain, May 8–11, ASME Paper No. GT2006-90838. [CrossRef]
Marini, R., and Girgis, S., 2007, “The Effect of Blade Leading Edge Platform Shape on Upstream Disk Cavity to Mainstream Flow Interaction of a High-Pressure Turbine Stage,” ASME Turbo Expo, Montreal, Canada, May 14–17, ASME Paper No. GT2007-27429. [CrossRef]
Schuepbach, P., Rose, M. G., Abhari, R. S., and Gier, J., 2011, “Influence of Rim Seal Purge Flow on the Performance of an Endwall-Profiled Axial Turbine,” ASME J. Turbomach., 133(2), p. 021001. [CrossRef]
Binder, A., Forster, W., Mach, K., and Rogge, H., 1987. “Unsteady Flow Interaction Caused by Stator Secondary Vortices in a Turbine Rotor,” ASME J. Turbomach., 109(2), pp. 251–257. [CrossRef]
Chaluvadi, V. S. P., Kalfas, A. I., and Hodson, H. P., 2004, “Vortex Transport and Blade Interactions in High Pressure Turbines,” ASME J. Turbomach., 126(3), pp. 395–406. [CrossRef]
Matsunuma, T., 2007, “Unsteady Flow Field of an Axial-Flow Turbine Rotor at a Low Reynolds Number,” ASME J. Turbomach., 129(2), pp. 360–371. [CrossRef]
Ch. Kasper, M.G., Rose, S. S., and Gier, J., 2008, “A Study of Unsteady Secondary Flow in a Water Flow Axial Turbine Model,” ASME Turbo Expo, Berlin, June 9–13, ASME Paper No. GT2008-50239. [CrossRef]
Jenny, P., Abhari, R. S., Rose, M. G., Brettschneider, M., and Gier, J., 2011. “A Low Pressure Turbine With Profiled End Walls and Purge Flow Operating With a Pressure Side Bubble,” ASME J. Turbomach., 134(6), p. 061038 [CrossRef].
Kupferschmied, P., Kopperl, O., Gizzi, W. P., and Gyarmathy, G., 2000, “Time Resolved Flow Measurements With Fast Aerodynamic Probes in Turbomachinery,” Meas. Sci. Technol., 11, pp. 1036–1054. [CrossRef]
Pfau, A., Schlienger, J., Kalfas, A. I., and Abhari, R. S., 2003, “Unsteady 3-Dimensional Flow Measurement Using a Miniature Virtual 4-Sensor Fast Response Aerodynamic Probe (FRAP),” ASME Turbo Expo, Atlanta, GA, June 16–19, ASME Paper No. GT2003-38128. [CrossRef]
Mansour, M., Chokani, N., Kalfas, A. I., and Abhari, R. S., 2008, “Time-Resolved Entropy Measurements Using a Fast Response Entropy Probe,” Meas. Sci. Technol., 19(11), p. 115401. [CrossRef]
Bashforth, F., and Adams, J., 1883, An Attempt to Test the Theories of Capillary Action by Comparing the Theoretical and Measured Forms of Drops of Fluid, With an Explanation of the Method of Integration Employed in Constructing the Tables Which Give the Theoretical Forms of Such Drops, Cambridge University Press, Cambridge, MA.
Schuepbach, P., Rose, M. G., Abhari, R. S., Germain, T., Raab, I., and Gier, J., 2010, “Effects of Suction and Injection Purge-Flow on the Secondary Flow Structures of a High-Work Turbine,” ASME J. Turbomach., 132(2), p. 021021. [CrossRef]
Schuepbach, P., Rose, M. G., Abhari, R. S., Germain, T., Raab, I., and Gier, J., 2008, “Improving Efficiency of a High-Work Turbine Using Non-Axisymmetric Endwalls. Part II—Time-Resolved Flow Physics,” ASME Turbo Expo, Berlin, June 9–13, ASME Paper No. GT2008-50470. [CrossRef]
Moore, J., 1973, “A Wake and an Eddy in a Rotating, Radial-Flow Passage—Part 1: Experimental Observations,” ASME J. Eng. Power, 95(3), pp. 205–212. [CrossRef]
Greitzer, E. M., Tan, C., and Graf, M., 2004, Internal Flow, Concepts and Applications, 1st ed., Cambridge University Press, Cambridge, MA.

Figures

Grahic Jump Location
Fig. 1

Illustration of leakage path and NGV1 exit and rotor exit measurement planes

Grahic Jump Location
Fig. 2

Comparison between measured and simulated relative flow yaw angle at the rotor exit for the nominal injection rate (IR = 0.8%)

Grahic Jump Location
Fig. 3

Radial distribution of circumferentially mass and time-averaged nondimensionalized streamwise vorticity ΩS (1/s) for the three investigated injection rates

Grahic Jump Location
Fig. 4

Time-averaged area plot in rotor relative frame of reference at the rotor exit. The parameter is the nondimensionalized streamwise vorticity ΩS (1/s) at low and high injection rates.

Grahic Jump Location
Fig. 5

Time space plot in absolute frame of reference of the nondimensionalized streamwise vorticity ΩS (1/s) for low and high injection rates at the rotor exit

Grahic Jump Location
Fig. 6

Time space plot in absolute frame of reference of the normalized static pressure (−) at the rotor exit (IR = 1.2% at 35% span)

Grahic Jump Location
Fig. 7

Unsteady spatial behavior of hub loss core at the rotor exit for minimum and maximum injection rates

Grahic Jump Location
Fig. 8

Radial distribution of circumferentially mass and time-averaged isentropic efficiency ηis (−) at the rotor exit for the three injection rates investigated

Grahic Jump Location
Fig. 9

Time-averaged area plot in rotor relative frame of reference at the rotor exit. The parameter is isentropic efficiency (−) at low and high injection rates.

Grahic Jump Location
Fig. 10

Radial distribution of circumferentially mass and time-averaged normalized total pressure and temperature at the rotor exit for the three investigated injection rates

Grahic Jump Location
Fig. 11

Top and side view of a typical particle track of particles leaving the rim seal cavity (IR = 0.8%) seen in the relative frame. The color of the particles indicates relative velocity.

Grahic Jump Location
Fig. 12

Position, relative velocity, and Euler work term of the particle presented in Fig. 11 and a free stream particle leaving the rotor blade row at the same radius. The parameters are plotted in function of the nondimensionalized axial position: 0 corresponds to the start of the particle at rotor inlet and 1 corresponds to the moment when the particle leaves the rotor domain.

Tables

Errata

Discussions

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