A TOBI (tangential on board injection), or preswirl, system is a critical component of a high pressure turbine cooling delivery system. Its efficient performance and characterization are critical because the blade and disk life depend on the accuracy of delivering the required flow at the correct temperature and pressure. This paper presents a TOBI flow discharge coefficient validation process applied to a low radius radial configuration starting from a 1dimensional (1D) network flow analysis to a 3 dimensional (3D) frozen rotor computational fluid dynamics (CFD) analysis of the rotor cooling air delivery system. The analysis domain commences in the combustor plenum stationary reference frame, includes the TOBI, transitions to the rotating reference frame as the flow travels through the rotating cover plate orifice, continues up the turbine disk into the slot bottom blade feed cavity, and terminates in the turbine blade. The present effort includes matching a 1D network model with 3D CFD results using simultaneous goal-matching of the pressure predictions throughout the circuit, defining test rig pressure measurements at critical “nondisturbing” locations for quanification of pressure ratio across the TOBI, and finally comparing the TOBI flow coefficient resulting from stationary cold flow tests with what was obtained from the 3D CFD results. An analysis of the results indicates that the discharge coefficient varies with the pressure ratio and that the traditional method of using a constant discharge coefficient extracted from a cold flow test run under choked conditions leads to overpredicting turbine cooling flows. The TOBI flow coefficient prediction for the present study compares well with the stationary data published by otherresearchers for the configuration under investigation and the process described in this paper is general for any TOBI configuration.

References

References
1.
Meierhofer
,
B.
, and
Franklin
,
C. J.
,
1981
, “
An Investigation of Preswirled Cooling Airflow to a Turbine Disk by Measuring the Air Temperature in the Rotating Channels
,” ASME Paper No. 81-GT-132.
2.
Scricca
,
J. A.
, and
Moore
,
K. D.
,
1997
, “
Effects of ‘Cooled’ Cooling Air on Pre-Swirl Nozzle Design
,” Pratt and Whitney, Technical Report No. NASA/CP-98-208527.
3.
Dittmann
,
M.
,
Geis
,
T.
,
Schramm
,
V.
,
Kim
,
S.
, and
Wittig
,
S.
,
2001
, “
Discharge Coefficients of a Pre-Swirl System in Secondary Air Systems
,” ASME Paper No. 2001-GT-0122.
4.
Yan
,
Y.
,
Farzaneh-Gord
,
M.
,
Lock
,
G. D.
,
Wilson
,
M.
, and
Owen
,
J. M.
,
2003
, “
Fluid Dynamics of a Pre-Swirl Rotor-Stator System
,”
ASME J. Turbomach.
,
125
(4), pp.
641
647
.10.1115/1.1578502
5.
Lewis
,
P.
,
Wilson
,
M.
,
Lock
,
G. D.
, and
Owen
,
J. M.
,
2007
, “
Physical Interpretation of Flow and Heat Transfer in Pre-Swirl Systems
,”
ASME J. Eng. Gas Turbines Power
,
129
(3), pp.
769
777
.10.1115/1.2436572
6.
Lichtarowicz
,
A.
,
Duggins
,
R.
, and
Markland
,
E.
,
1965
, “
Discharge Coefficients for Incompressible Non-Cavitating Flow Through Long Orifices
,”
J. Mech. Eng. Sci.
,
7
(
2
), pp.
210
219
.10.1243/JMES_JOUR_1965_007_029_02
7.
McGreehan
,
W. F.
, and
Schotsch
,
M. J.
,
1987
, “
Flow Characteristics of Long Orifices With Rotation and Corner Radiusing
,” ASME Paper No. 87-GT-162.
8.
Kakade
,
V. U.
,
Lock
,
G. D.
,
Wilson
,
M.
,
Owen
,
J. M.
, and
Mayhew
,
J. E.
,
2009
, “
Effect of Radial Location of Nozzles on Heat Transfer in Pre-Swirl Cooling System
,”
ASME
, Paper No. GT2009-5909010.1115/GT2009-59090.
9.
Laurello
,
V.
,
Yuri
,
M.
,
Fujii
,
K.
,
Ishizaka
,
K.
,
Nakamura
,
T.
, and
Nishimura
,
H.
,
2004
, “
Measurement and Analysis of an Efficient Turbine Rotor Pump Work Reduction System Incorporating Pre-Swirl Nozzles and a Free Vortex Pressure Augmentation Chamber
,”
ASME
, Paper No. GT2004-53090.10.1115/GT2004-53090
10.
Bricaud
,
C.
,
Geis
,
T.
,
Dullenkopf
,
K.
, and
Bauer
,
H.-J.
,
2007
, “
Measurement and Analysis of Aerodynamic and Thermodynamic Losses in Pre-Swirl System Arrangements
,”
ASME
, Paper No. GT2007-27191.10.1115/GT2007-27191
11.
Mirzamoghadam
,
A. V.
,
Ramerth
,
D. L.
,
Kiratsingh
,
A.
, and
Banda
,
G.
,
2011
, “
A Probabilistic Secondary Flow System Design Process for Gas Turbine Engines
,”
ASME J. Eng. Gas Turbines Power
,
133
(
9
), p.
092502
.10.1115/1.4002829
12.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single-Sample Experiments
,”
Mech. Eng.
,
75
, pp. 3–8.
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