Cooling methods are strongly needed for the turbine blade tips to ensure a long durability and safe operation. Improving the internal convective cooling is therefore required to increase the blade tip life. A common way to cool the tip is to use serpentine passages with 180-deg turns under the blade tip cap. In this paper, enhanced heat transfer of a blade tip cap has been investigated numerically. The computational models consist of a two-pass channel with a 180-deg turn and various arrays of pin fins mounted on the tip cap, and a smooth two-pass channel. The inlet Reynolds number is ranging from 100,000 to 600,000. The computations are 3D, steady, incompressible, and nonrotating. Details of the 3D fluid flow and heat transfer over the tip walls are presented. The effects of pin-fin height, diameter, and pitches on the heat transfer enhancement on the blade tip walls are observed. The overall performances of ten models are compared and evaluated. It is found that due to the combination of turning, impingement, and pin-fin crossflow, the heat transfer coefficient of the pin-finned tip is a factor of 2.67 higher than that of a smooth tip. This augmentation is achieved at the expense of a penalty of pressure drop around 30%. Results show that the intensity of heat transfer enhancement depends upon pin-fin configuration and arrangement. It is suggested that pin fins could be used to enhance the blade tip heat transfer and cooling.
Issue Section:
Heat Transfer Enhancement
Keywords:
channel flow,
convection,
cooling,
engines,
gas turbines,
tip wall,
pin fins,
enhancement,
computation,
gas turbine cooling
1.
Han
, J. C.
, Dutta
, S.
, and Ekkad
, S. V.
, 2000, Gas Turbine Heat Transfer and Cooling Technology
, Taylor & Francis
, New York
.2.
Goldstein
, R. J.
, 2001, Heat Transfer in Gas Turbine Systems
, New York Academy of Sciences
, New York
.3.
Sundén
, B.
, and Faghri
, M.
, 2001, Heat Transfer in Gas Turbines
, WIT
, UK
.4.
Han
, J. C.
, 2004, “Recent Studies in Turbine Blade Cooling
,” Int. J. Rotating Mach.
1023-621X, 10
(6
), pp. 1
–15
.5.
Bunker
, R. S.
, 2000, “ A Review of Turbine Blade Tip Heat Transfer
,” Annals of the New York Academy of Sciences
, R. J.
Goldstein
, ed., New York Academy of Sciences
, New York
, pp. 64
–79
.6.
Bunker
, R. S.
, 2006, “Axial Turbine Blade Tips: Function, Design and Durability
,” J. Propul. Power
0748-4658, 22
(2
), pp. 271
–285
.7.
Ekkad
, S. V.
, Pamula
, G.
, and Shantiniketanam
, M.
, 2000, “Detailed Heat Transfer Measurements Inside Straight and Tapered Two-Pass Channels With Rib Turbulators
,” Exp. Therm. Fluid Sci.
0894-1777, 22
, pp. 155
–163
.8.
Son
, S. Y.
, Kihm
, K. D.
, and Han
, J. C.
, 2002, “PIV Flow Measurements for Heat Transfer Characterization in Two-Pass Square Channels With Smooth and 90° Ribbed Walls
,” Int. J. Heat Mass Transfer
0017-9310, 45
, pp. 4809
–4822
.9.
Al-Hadhrami
, L.
, Griffith
, T.
, and Han
, J. C.
, 2003, “Heat Transfer in Two-Pass Rotating Rectangular Channels (AR=2) With Five Different Orientations of 45-deg V-Shaped Rib Turbulators
,” ASME J. Heat Transfer
0022-1481, 125
, pp. 232
–242
.10.
Astarita
, T.
, Cardone
, G.
, and Carlomagno
, G. M.
, 2002, “Convective Heat Transfer in Ribbed Channels With a 180° Turn
,” Exp. Fluids
0723-4864, 33
, pp. 90
–100
.11.
Liou
, T. M.
, Chen
, M. Y.
, and Wang
, Y. M.
, 2003, “Heat Transfer, Fluid Flow and Pressure Measurements Inside a Rotating Two-Pass Duct With Detached 90-deg Ribs
,” ASME J. Turbomach.
0889-504X, 125
, pp. 565
–574
.12.
Liou
, T. M.
, Hwang
, Y. S.
, and Li
, Y. C.
, 2006, “Flowfield and Pressure Measurements in a Rotating Two-Pass Duct With Staggered Rounded Ribs Skewed 45-deg to the Flow
,” ASME J. Turbomach.
0889-504X, 128
, pp. 340
–348
.13.
Fu
, W. L.
, Wright
, L. M.
, and Han
, J. C.
, 2005, “Heat Transfer in Two-Pass Rotating Rectangular Channels (AR=1:2 and AR=1:4) With 45-deg Angled Rib Turbulators
,” ASME J. Turbomach.
0889-504X, 127
, pp. 164
–174
.14.
Fu
, W. L.
, Wright
, L. M.
, and Han
, J. C.
, 2006, “Heat Transfer in Two-Pass Rotating Rectangular Channels (AR=1:2) With Discrete Ribs
,” J. Thermophys. Heat Transfer
0887-8722, 20
(3
), pp. 569
–582
.15.
Liu
, Y. H.
, Wright
, L. M.
, Fu
, W. L.
, and Han
, J. C.
, 2007, “Rib Spacing Effect on Heat Transfer in Rotating Two-Pass Ribbed Channel
,” J. Thermophys. Heat Transfer
0887-8722, 21
(3
), pp. 582
–595
.16.
Kim
, K. M.
, Lee
, D. H.
, Rhee
, D. H.
, and Cho
, H. H.
, 2006, “Local Heat/Mass Transfer Phenomena in Rotating Passage, Part 1: Smooth Passage
,” J. Thermophys. Heat Transfer
0887-8722, 20
(2
), pp. 188
–198
.17.
Kim
, K. M.
, Lee
, D. H.
, Rhee
, D. H.
, and Cho
, H. H.
, 2006, “Local Heat/Mass Transfer Phenomena in Rotating Passage, Part 2: Angled Ribbed Passage
,” J. Thermophys. Heat Transfer
0887-8722, 20
(2
), pp. 199
–210
.18.
Lee
, S. W.
, Ahn
, H. S.
, and Lau
, S. C.
, 2007, “Heat (mass) Transfer Distribution in a Two-Pass Trapezoidal Channel With a 180-deg Turn
,” ASME J. Heat Transfer
0022-1481, 129
, pp. 1529
–1537
.19.
Lucci
, J. M.
, Amano
, R. S.
, and Guntur
, K.
, 2007, “Turbulent Flow and Heat Transfer in Variable Geometry U-Bend Blade Cooling Passage
,” ASME
Paper No. GT2007-27120.20.
Jenkins
, S. C.
, Zehnder
, F.
, and Shevchuk
, I. V.
, 2008, “The Effect of Ribs and Tip Wall Distance on Heat Transfer for a Varying Aspect Ratio Two-Pass Ribbed Internal Cooling Channel
,” ASME
Paper No. GT2008-51270.21.
Shevchuk
, I. V.
, Jenkins
, S. C.
, and Zehnder
, F.
, 2008, “Validation and Analysis of Numerical Results for a Varying Aspect Ratio Two-Pass Internal Cooling Channel
,” ASME
Paper No. GT2008-51219.22.
Metzger
, D. E.
, Berry
, R. A.
, and Bronson
, J. P.
, 1982, “Developing Heat Transfer in Rectangular Ducts With Staggered Arrays of Short Pin Fins
,” ASME J. Heat Transfer
0022-1481, 104
, pp. 700
–706
.23.
Lau
, S. C.
, Kim
, Y. S.
, and Han
, J. C.
, 1987, “Local Endwall Heat/Mass Distributions in Pin Fin Channels
,” AIAA J. Thermophys. Heat Transfer
, 1
(4
), pp. 365
–372
.24.
Chyu
, M. K.
, Hsing
, Y. C.
, Shih
, T. I. P.
, and Natarajan
, V.
, 1999, “Heat Transfer Contributions of Pins and Endwall in Pin-Fin Arrars: Effect of Thermal Boundary Condition Modeling
,” ASME J. Turbomach.
0889-504X, 121
, pp. 257
–263
.25.
Goldstein
, R. J.
, Jabbari
, M. Y.
, and Chen
, S. B.
, 1994, “Convective Mass Transfer and Pressure Loss Characteristics of Staggered Short Pin-Fin Arrays
,” Int. J. Heat Mass Transfer
0017-9310, 37
(1
), pp. 149
–160
.26.
Wright
, L. M.
, Lee
, E.
, and Han
, J. C.
, 2004, “Effect of Rotating on Heat Transfer in Rectangular Channels With Pin Fins
,” J. Thermophys. Heat Transfer
0887-8722, 18
(2
), pp. 263
–272
.27.
Ames
, F. E.
, Dvorak
, L. A.
, and Morrow
, M. J.
, 2005, “Turbulent Augmentation of Internal Convection Over Pins in Staggered-Pin Fin Arrays
,” ASME J. Turbomach.
0889-504X, 127
, pp. 183
–190
.28.
Sahiti
, N.
, Lemouedda
, A.
, Stojkovic
, D.
, Durst
, F.
, and Franz
, E.
, 2006, “Performance Comparison of Pin Fin In-Duct Flow Arrays With Various Pin Cross-Section
,” Appl. Therm. Eng.
1359-4311, 26
, pp. 1176
–1192
.29.
Su
, G. G.
, Chen
, H. C.
, and Han
, J. C.
, 2007, “Computation of Flow and Heat Transfer in Rotating Rectangular Channels (AR=4:1) With Pin-Fins by a Reynolds Stress Turbulence Model
,” ASME J. Heat Transfer
0022-1481, 129
, pp. 685
–696
.30.
Chang
, S. W.
, Yang
, T. L.
, Huang
, C. C.
, and Chiang
, K. F.
, 2008, “Endwall Heat Transfer and Pressure Drop in Rectangular Channels With Attached and Detached Circular Pin-Fin Array
,” Int. J. Heat Mass Transfer
0017-9310, 51
, pp. 5247
–5259
.31.
Bunker
, R. S.
, 2008, “The Augmentation of Internal Blade Tip-Cap Cooling by Arrays of Shaped Pins
,” ASME J. Turbomach.
0889-504X, 130
, p. 041007
.32.
Saha
, A.
, and Acharya
, S.
, 2004, “Unsteady Simulation of Turbulent Flow and Heat Transfer in a Channel With Periodic Array of Cubic Pin-Fins
,” Numer. Heat Transfer, Part A
1040-7782, 46
(8
), pp. 731
–763
.33.
Etemad
, S.
, and Sundén
, B.
, 2006, “Numerical Investigation of Turbulent Heat Transfer in a Rectangular-Sectioned 90° Bend
,” Numer. Heat Transfer, Part A
1040-7782, 49
(4
), pp. 323
–343
.34.
Kim
, K. Y.
, and Lee
, Y. M.
, 2007, “Design Optimization of Internal Cooling Passage With V-shaped Ribs
,” Numer. Heat Transfer, Part A
1040-7782, 51
(11
), pp. 1103
–1118
.35.
Chen
, H. C.
, Jang
, Y. J.
, and Han
, J. C.
, 2000, “Computation of Heat Transfer in Rotating Two-Pass Square Channels by a Second-Moment Closure Model
,” Int. J. Heat Mass Transfer
0017-9310, 43
, pp. 1603
–1616
.36.
Jang
, Y. J.
, Chen
, H. C.
, and Han
, J. C.
, 2001, “Computation of Flow and Heat Transfer in Two-Pass Channels With 60-deg Ribs
,” ASME J. Heat Transfer
0022-1481, 123
, pp. 563
–575
.37.
Al-Qahtani
, M.
, Jang
, Y. J.
, Chen
, H. C.
, and Han
, J. C.
, 2002, “Flow and Heat Transfer in Rotating Two-Pass Rectangular Channels (AR=2) by Reynolds Stress Turbulence Model
,” Int. J. Heat Mass Transfer
0017-9310, 45
, pp. 1823
–1838
.38.
Jia
, R.
, Sunden
, B.
, and Faghri
, M.
, 2005, “Computational Analysis of Heat Transfer Enhancement in Square Ductrs With V-shaped Ribs—Turbine Blade Cooling
,” ASME J. Heat Transfer
0022-1481, 127
, pp. 425
–433
.39.
Jia
, R.
, Sunden
, B.
, and Faghri
, M.
, 2007, “A New Low Reynolds Stress Transport Model for Heat Transfer and Fluid in Engineering Applications
,” ASME J. Heat Transfer
0022-1481, 129
, pp. 434
–440
.40.
Yang
, C. S.
, Jeng
, D. Z.
, Yih
, K. A.
, Gau
, C.
, Aung
, W.
, 2009, “Numerical and Analytical Study of Reversed Flow and Heat Transfer in a Heated Vertical Duct
,” ASME J. Heat Transfer
0022-1481, 131
, p. 072501
.41.
Zhou
, F.
, Lagrone
, J.
, and Acharya
, S.
, 2007, “Internal Cooling in 4:1 AR Passages at High Rotation Numbers
,” ASME J. Heat Transfer
0022-1481, 129
, pp. 1666
–1675
.42.
Liu
, Y. H.
, Huh
, M.
, Han
, J. C.
, Chopra
, S.
, 2008, “Heat Transfer in a Two-Pass Rectangular Channel (AR=1:4) Under High Rotation Numbers
,” ASME J. Heat Transfer
0022-1481, 130
, p. 081701
.43.
Xie
, G. N.
, Sundén
, B.
, Wang
, L. K.
, and Utriainen
, E.
, 2009, “Enhanced Internal Heat Transfer on the Tip-wall in a Rectangular Two-pass Channel by Pin-Fin Arrays
,” Numer. Heat Transfer, Part A
1040-7782, 55
, pp. 739
–761
.44.
Choudhury
, D.
, 1993, “Introduction to the Renormalization Group Method and Turbulence Modeling
,” Fluent Inc. Technical Paper No. TM-107.Copyright © 2010
by American Society of Mechanical Engineers
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