Individual nozzle guide vanes (NGV’s) in modern aeroengines are often cast as a single piece with integral hub and casing endwalls. When in operation, there is a leakage flow through the chord-wise interplatform gaps. An investigation into the effect of this leakage flow on turbine performance is presented. Efficiency measurements and NGV exit area traverse data from a low-speed research turbine are reported. Tests show that this leakage flow can have a significant impact on turbine performance, but that below a threshold leakage fraction this penalty does not rise with increasing leakage flow rate. The effect of various seal clearances are also investigated. Results from steady-state simulations using a three-dimensional multiblock Reynolds-averaged Navier-Stokes solver are presented with particular emphasis paid to the physics of the mainstream/leakage interaction and the loss generation.

1.
Aunapu
,
N.
,
Volino
,
R.
,
Flack
,
K.
, and
Stoddard
,
R.
, 2000, “
Secondary Flow Measurements in a Turbine Passage With Endwall Flow Modification
,” ASME Paper No. 2000-GT-0212.
2.
Cardwell
,
N.
,
Sundaram
,
N.
, and
Thole
,
K.
, 2005, “
Effects of Mid-Passage Gap, Endwall Misalignment, and Roughness on Endwall Fil Cooling
,” ASME Paper No. GT2005-68900.
3.
Ranson
,
W.
,
Thole
,
K.
, and
Cunha
,
F.
, 2005, “
Adiabatic Effectiveness Measurements and Predictions of Leakage Flows Along a Blade Endwall
,”
ASME J. Turbomach.
0889-504X, pp.
609
618
.
4.
Pullan
,
G.
,
Denton
,
J.
, and
Dunkley
,
M.
, 2003, “
An Experimental and Computational Study of the Formation of a Streamwise Shed Vortex in a Turbine Stage
,”
ASME J. Turbomach.
0889-504X, pp.
291
297
.
5.
Ower
,
E.
, and
Pankhurst
,
R.
, 1965,
Measurement of Air Flow
,
4th ed.
,
Pergamon
,
New York
.
6.
Beckwith
,
T.
,
Marangoni
,
R.
, and
Lienhard
,
J.
, 1993,
Mechanical Measurements
,
5th ed.
Addison–Wesley
,
Reading, MA
.
7.
Denton
,
J. D.
, 1990, “
The Calculation of Three-Dimensional Viscous Flow Through Multistage Turbomachines
,” ASME Paper No. 90-GT-19.
8.
Pullan
,
G.
, and
Denton
,
J.
, 2003, “
Numerical Simulations of Vortex-Turbine Blade Interaction
,”
Conference Proceedings: 5th European Conference on Turbomachinery: Fluid Dynamics, and Thermodynamics
.
9.
Denton
,
J. D.
, 1993, “
Loss Mechanisms in Turbomachines
,”
ASME J. Turbomach.
0889-504X,
115
, pp.
621
656
.
10.
Dawes
,
W.
, 1987, “
Application of a Three-Dimensional Viscous Compressible Flow Solver to a High-Speed Centrifugal Compressor Rotor-Secondary Flow and Loss Generation
,” IMECHE Paper No. C261/87.
You do not currently have access to this content.