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

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