Leaf seals are filament seals for use at static to rotating interfaces in the engine secondary air system. They offer reduced leakage rates and better off-design performance over conventional labyrinth seals. If compared with advanced brush seals, leaf seals are more compliant due to their lower stiffness and can withstand higher axial pressure differences. Although leaf seals can exhibit hydrodynamic air-riding, this is not always the case and seal–rotor contact can occur. As a result, friction between the leaf tips and the rotor causes heat generation and wear. To predict the diameter of the rotating shaft and the seal life, the shaft and seal interface temperature needs to be estimated. In the steady state, this is determined by the ratio of convective heat transfer through the seal to that through the shaft. To that end, the convective heat transfer characteristics of the flow over the shaft around the seal are required to build accurate thermal models. In this paper, the convective heat transfer coefficient (HTC) distribution in the close vicinity of a typical leaf seal is investigated in a new test facility. The experimental setup and test method are described in detail, and accuracy considerations are included. The methodology employed to derive HTC is explained with reference to an analogous computational fluid dynamics (CFD) model. The importance of the choice of an appropriate driving gas temperature is demonstrated. Experimental HTC maps are presented for a blow-down seal geometry operating over a range of engine representative pressure ratios. Insight is gained into the flow field characteristics and heat transfer around the seal.

References

References
1.
Nakane
,
H.
,
Maekawa
,
A.
,
Akita
,
E.
,
Akagi
,
K.
,
Nakano
,
T.
,
Nishimoto
,
S.
,
Hashimoto
,
S.
,
Shinohara
,
T.
, and
Uehara
,
H.
,
2004
, “
The Development of High Performance Leaf Seals
,”
ASME J. Eng. Gas Turbines Power
,
126
(
2
), pp.
342
350
.
2.
Mitsubishi Hitachi Power Systems Group, 2015, “
Mitsubishi Hitachi Power Systems
,” Mitsubishi Hitachi Power Systems Group, Yokohama Japan, accessed Nov. 9, 2015, http://www.mhps.com/en/technology/business/power/ /service/steam/seal.html
3.
Jahn
, I
. H.
,
Gillespie
,
D. R. H.
, and
Cooper
,
P.
,
2013
, “
Hydrodynamic Air-Riding in Leaf Seals
,”
ASME
Paper No. GT2013-95585.
4.
Owen
,
A. K.
,
Guo
,
S. M.
, and
Jones
,
T. V.
,
2003
, “
An Experimental and Theoretical Study of Brush Seal and Shaft Thermal Interaction
,”
ASME
Paper No. GT2003-38276.
5.
Pekris
,
M. J.
,
Franceschini
,
G.
,
Owen
,
A. K.
,
Jones
,
T. V.
, and
Gillespie
,
D. R. H.
,
2016
, “
Analytical Modeling and Experimental Validation of Heating at the Leaf Seal/Rotor Interface
,”
ASME
Paper No. GT2016-57577.
6.
Epstein
,
A. H.
,
Guenette
,
G. R.
,
Norton
,
R. J. G.
, and
Chao
,
Y. Z.
,
1986
, “
High-Frequency Response Heat-Flux Gauge
,”
Rev. Sci. Instrum.
,
57
(
4
), pp.
639
649
.
7.
Piccini
,
E.
,
Guo
,
S. M.
, and
Jones
,
T. V.
,
2000
, “
The Development of a New Direct-Heat-Flux Gauge for Heat-Transfer Facilities
,”
Meas. Sci. Technol.
,
11
(
4
), pp.
342
349
.
8.
Oldfield
,
M. L. G.
,
2008
, “
Impulse Response Processing of Transient Heat Transfer Gauge Signals
,”
ASME J. Turbomach.
,
130
(
2
), p.
021023
.
9.
Ling
,
J. P. C. W.
,
Ireland
,
P. T.
, and
Turner
,
L.
,
2004
, “
A Technique for Processing Transient Heat Transfer Liquid Crystal Experiments in the Presence of Lateral Conduction
,”
ASME J. Turbomach.
,
126
(
2
), pp.
247
258
.
10.
Billiard
,
N.
,
Iliopoulou
,
V.
,
Ferrara
,
F.
, and
Dénos
,
R.
,
2002
, “
Data Reduction and Thermal Product Determination for Single and Multi-Layered Substrates Thin-Film Gauges
,”
The 16th Symposium on Measuring Techniques in Transonic and Supersonic Flow in Cascades and Turbomachines
, Cambridge, UK.
11.
Guo
,
S. M.
,
Lai
,
C. C.
,
Jones
,
T. V.
,
Oldfield
,
M. L. G.
,
Lock
,
G. D.
, and
Rawlinson
,
A. J.
,
2000
, “
Influence of Surface Roughness on Heat Transfer and Effectiveness for a Fully Film Cooled Nozzle Guide Vale Measured by Wide Band Liquid Crystals and Direct Heat Flux Gauges
,”
ASME J. Turbomach.
,
122
(
4
), pp.
709
716
.
12.
Guo
,
S. M.
,
Oldfield
,
M. L. G.
, and
Rawlinson
,
A. J.
,
2002
, “
Influence of Discrete Pin Shaped Surface Roughness (P-Pins) on Heat Transfer and Aerodynamics of Film Cooled Aerofoil
,”
ASME
Paper No. GT2002-30179.
13.
BSI
,
1981
, “
British Standard Measurement of Fluid Flow in Closed Conduits
,” British Standards Institution, London, Standard No. BS1042: Section 1.1.
14.
Kays
,
W.
,
Crawford
,
M.
, and
Weigand
,
B.
,
2004
,
Convective Heat and Mass Transfer
,
4th ed.
,
McGraw-Hill
,
New York
.
15.
Bayley
,
F. J.
, and
Long
,
C. A.
,
1992
, “
A Combined Experimental and Theoretical Study of Flow and Pressure Distributions in a Brush Seal
,”
ASME J. Eng. Gas Turbines Power
,
115
(
2
), pp.
404
410
.
16.
Chew
,
J. W.
,
Lapworth
,
B. L.
, and
Millener
,
P. J.
,
1995
, “
Mathematical Modeling of Brush Seals
,”
Int. J. Heat Fluid Flow
,
16
(
6
), pp.
493
500
.
17.
Dogu
,
Y.
,
2005
, “
Investigation of Brush Seal Flow Characteristics Using Bulk Porous Medium Approach
,”
ASME J. Eng. Gas Turbines Power
,
127
(
1
), pp.
136
144
.
18.
Qiu
,
B.
, and
Li
,
J.
,
2013
, “
Numerical Investigation on the Heat Transfer Behavior of Brush Seals Using Combined Computational Fluid Dynamics and Finite Element Method
,”
ASME J. Heat Transfer
,
135
(
12
), p.
122601
.
19.
Flouros
,
M.
,
Hendrick
,
P.
,
Outirba
,
B.
,
Cottier
,
F.
, and
Proestler
,
S.
,
2014
, “
Thermal and Flow Phenomena Associated With the Behavior of Brush Seals in Aero Engine Bearing Chambers
,”
ASME
Paper No. GT2014-25538.
20.
Kays
,
W. M.
, and
Leung
,
E. Y.
,
1963
, “
Heat Transfer in Annular Passages: Hydrodynamically Developed Turbulent Flow With Arbitrarily Prescribed Heat Flux
,”
Int. J. Heat Mass Transfer
, pp.
537
557
.
21.
Kuzay
,
T. M.
, and
Scott
,
C. J.
,
1977
, “
Turbulent Heat Transfer Studies in an Annulus With Inner Cylinder Rotation
,”
ASME J. Heat Transfer
,
99
(
1
), pp.
12
19
.
22.
Childs
,
P. R. N.
, and
Turner
,
A. B.
,
1994
, “
Heat Transfer on the Surface of a Cylinder Rotating in an Annulus at High Axial and Rotational Reynolds Numbers
,”
10th International Heat Transfer Conference
, Paper No. 4-EC-5.
23.
Moffat
,
R. J.
,
1982
, “
Contributions to the Theory of Single-Sample Uncertainty Analysis
,”
ASME J. Fluids Eng.
,
104
(
2
), pp.
250
260
.
You do not currently have access to this content.