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Research Papers: Heat Transfer Enhancement

Role of Chamfering Angles and Flow Through Slit on Heat Transfer Augmentation Behind a Surface-Mounted Rib

[+] Author and Article Information
Md Shaukat Ali

Mechanical Engineering Department,
College of Engineering,
Qassim University,
Buraidah 51452, Saudi Arabia
e-mail: shaukat779@gmail.com

Andallib Tariq

Mechanical and Industrial
Engineering Department,
Indian Institute of Technology Roorkee,
Roorkee 247667, India
e-mail: tariqfme@iitr.ac.in

B. K. Gandhi

Mechanical and Industrial
Engineering Department,
Indian Institute of Technology Roorkee,
Roorkee 247667, India
e-mail: bkgmefme@iitr.ac.in

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received September 20, 2015; final manuscript received June 1, 2016; published online June 28, 2016. Assoc. Editor: Danesh / D. K. Tafti.

J. Heat Transfer 138(11), 111901 (Jun 28, 2016) (16 pages) Paper No: HT-15-1612; doi: 10.1115/1.4033747 History: Received September 20, 2015; Revised June 01, 2016

Detailed heat transfer and flow field investigations behind a surface-mounted slitted trapezoidal rib have been performed using liquid crystal thermography (LCT) and particle image velocimetry (PIV). In the accomplished experiments, the effects of varying the chamfering angle over the trailing edge of a rib with a centrally placed longitudinal continuous slit carrying an open area ratio equivalent to 25% were studied. The chamfering angle has been varied from 0 to 20 deg in a step of 5 deg. Experiments were carried out for four different Reynolds numbers ranging in between 9400 and 61,480, which were based upon the hydraulic diameter of the rectangular duct. The motive behind the present work is to systematically study the effect of change in chamfering angle of a trapezoidal rib with a centrally placed continuous slit over the flow and heat transfer parameters. Emphasis was made to identify the flow parameters responsible for augmentation in surface heat transfer coefficients (HTCs). Results are presented in terms of mean and rms velocity fields, stream traces, Reynolds stress, vorticity, and surface- and spanwise-averaged augmentation Nusselt number distribution. The reattachment length and the average augmentation Nusselt number have been evaluated for all of the different configurations. Entire configurations under selected range of Reynolds number led to the rise in heat transfer enhancement as against the flat surface without the rib. It is observed that slitted ribs cause shorter reattachment length and better heat transfer enhancement in the downstream vicinity of the rib. Further, the recirculation area behind the rib is enlarged to the point of spanning the nearby downstream vicinity of the rib (x/e<4), which signifies the zone of maximum heat transfer enhancement due to the effect of flow coming out of the slit. Salient critical points and foci of secondary recirculation patterns are extracted, which provides clues to the physical process occurring in the flow, which were responsible for the mixing enhancement behind slitted trapezoidal rib geometries.

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References

Han, J. C. , 1984, “ Heat Transfer and Friction in Channels With Two Opposite Rib-Roughened Walls,” ASME J. Heat Transfer, 106(4), pp. 774–781. [CrossRef]
Han, J. C. , Park, J. S. , and Lei, C. K. , 1985, “ Heat Transfer Enhancement in Channels With Turbulence Promoters,” ASME J. Eng. Gas Turbines Power, 107(3), pp. 628–635. [CrossRef]
Chandra, P. R. , Fontenot, M. L. , and Han, J. C. , 1998, “ Effect of Rib Profiles on Turbulent Channel Flow Heat Transfer,” AIAA J. Thermophys. Heat Transfer, 12(1), pp. 116–118. [CrossRef]
Taslim, M. E. , and Lenkong, A. , 1998, “ 45 deg Staggered Rib Heat Transfer Coefficient Measurements in a Square Channel,” ASME J. Turbomach., 120(3), pp. 571–580. [CrossRef]
Ekkad, S. V. , and Han, J. C. , 1997, “ Detailed Heat Transfer Distributions in Two-Pass Square Channels With Rib Turbulators,” Int. J. Heat Mass Transfer, 40(11), pp. 2525–2537. [CrossRef]
Gad-el-Hak, M. , 2000, Flow Control: Passive, Active and Reactive Flow Management, Cambridge University Press, Cambridge, UK.
Islam, M. S. , Haga, K. , Kaminaga, M. , Hino, R. , and Monde, M. , 2002, “ Experimental Analysis of Turbulent Flow Structure in a Fully Developed Rib-Roughened Rectangular Channel With PIV,” Exp. Fluids, 33(2), pp. 296–306. [CrossRef]
Panigrahi, P. K. , and Tariq, A. , 2003, “ Liquid Crystal Heat Transfer Measurements in a Rectangular Channel With Solid and Slit Rib,” J. Visualization, 6(4), pp. 407–416. [CrossRef]
Wang, L. , and Sunden, B. , 2007, “ Experimental Investigation of Local Heat Transfer in a Square Duct With Various-Shaped Ribs,” Heat Mass Transfer, 43(8), pp. 759–766. [CrossRef]
Wang, L. , Hejcik, J. , and Sunden, B. , 2007, “ PIV Measurement of Separated Flow in a Square Channel With Streamwise Periodic Ribs on One Wall,” ASME J. Fluids Eng., 129(7), pp. 834–841. [CrossRef]
Wang, L. , Salewski, M. , and Sunden, B. , 2010, “ Turbulent Flow in a Ribbed Channel: Flow Structures in the Vicinity of a Rib,” Exp. Therm. Fluid Sci., 34(2), pp. 165–176. [CrossRef]
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 Degrees to the Flow,” ASME J. Turbomach., 128(2), pp. 340–348. [CrossRef]
Sunden, B. , 2011, “ Convective Heat Transfer and Fluid Flow Physics in Some Ribbed Ducts Using Liquid Crystal Thermography and PIV Measuring Techniques,” Heat Mass Transfer, 47(8), pp. 899–910. [CrossRef]
Mikielewicz, D. , Stasiek, A. , Jewartowski, M. , and Stasiek, J. , 2012, “ Measurements of Heat Transfer Enhanced by the Use of Transverse Vortex Generators,” Appl. Therm. Eng., 49, pp. 1–12. [CrossRef]
Yemenici, O. , Firatoglu, Z. A. , and Umur, H. , 2012, “ An Experimental Investigation of Flow and Heat Transfer Characteristics Over Blocked Surfaces in Laminar and Turbulent Flows,” Int. J. Heat Mass Transfer, 55(13–14), pp. 3641–3649. [CrossRef]
Liou, T. M. , and Kao, C. F. , 1988, “ Experimental Measurements of Flow Past Double-Sided Wall Obstacles in a Rectangular Duct,” Exp. Therm. Fluid Sci., 1(2), pp. 135–146. [CrossRef]
Liou, T. M. , and Kao, C. F. , 1988, “ Symmetric and Asymmetric Turbulent Flows in a Rectangular Duct With a Pair of Ribs,” ASME J. Fluids Eng., 110(4), pp. 373–379. [CrossRef]
Panigrahi, P. K. , and Acharya, S. , 2004, “ Multi-Modal Forcing of the Turbulent Separated Shear Flow Past a Rib,” ASME J. Fluids Eng., 126(1), pp. 22–31. [CrossRef]
Tariq, A. , Panigrahi, P. K. , and Muralidhar, K. , 2004, “ Flow and Heat Transfer in the Wake of a Surface-Mounted Rib With a Slit,” Exp. Fluids, 37(5), pp. 701–719. [CrossRef]
Tariq, A. , 2004, “ Heat Transfer Enhancement and Fluid Flow Transport Phenomena Behind Surface Mounted Solid and Permeable Ribs,” Ph.D. dissertation, IIT Kanpur, Kanpur, India.
Panigrahi, P. K. , Schroder, A. , and Kompenhans, J. , 2006, “ PIV Investigation of Flow Behind Surface Mounted Permeable Ribs,” Exp. Fluids, 40(2), pp. 277–300. [CrossRef]
Fröhlich, J. , Mellen, C. P. , Rodi, W. , Temmerman, L. , and Leschziner, M. A. , 2005, “ Highly Resolved Large-Eddy Simulation of Separated Flow in a Channel With Streamwise Periodic Constrictions,” J. Fluids Mech., 526, pp. 19–66 [CrossRef]
Liou, T. M. , and Hwang, J. J. , 1993, “ Effect of Ridge Shapes on Turbulent Heat Transfer and Friction in Rectangular Channel,” Int. J. Heat Mass Transfer, 36(4), pp. 931–940. [CrossRef]
Ahn, S. W. , 2001, “ The Effect of Roughness Type on Friction Factors and Heat Transfer in Roughened Rectangular Duct,” Int. Commun. Heat Mass Transfer, 28(7), pp. 933–942. [CrossRef]
Kamali, R. , and Binesh, A. R. , 2008, “ The Importance of Rib Shape Effects on the Local Heat Transfer and Flow Friction Characteristics of Square Ducts With Ribbed Internal Surfaces,” Int. Commun. Heat Mass Transfer, 35(8), pp. 1032–1040. [CrossRef]
Hwang, J. J. , and Liou, T. M. , 1997, “ Heat Transfer Augmentation in a Rectangular Channel With Slit Rib-Turbulators on Two Opposite Walls,” ASME J. Turbomach., 119(3), pp. 617–623. [CrossRef]
Hwang, J. J. , 1998, “ Heat Transfer-Friction Characteristic Comparison in Rectangular Ducts With Slit and Solid Ribs Mounted on One Wall,” ASME J. Heat Transfer, 120(3), pp. 709–716. [CrossRef]
Kukreja, R. T. , and Lau, S. C. , 1998, “ Distribution of Local Heat Transfer Coefficient on Surfaces With Solid and Perforated Ribs,” Enhanced Heat Transfer, 5(1), pp. 9–21. [CrossRef]
Panigrahi, P. K. , Schroeder, A. , and Kompenhans, J. , 2008, “ Turbulent Structures and Budgets Behind Permeable Ribs,” Exp. Therm. Fluid Sci., 32(4), pp. 1011–1033. [CrossRef]
Liou, T. M. , Chen, M. Y. , and Chang, K. , 2003, “ Spectrum Analysis of Fluid Flow in a Rotating Two-Pass Duct With Detached 90° Ribs,” Exp. Therm. Fluid Sci., 27(3), pp. 313–321. [CrossRef]
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., 125(3), pp. 565–574. [CrossRef]
Panigrahi, P. K. , 2009, “ PIV Investigation of Flow Behind Surface Mounted Detached Square Cylinder,” ASME J. Fluids Eng., 131(1), p. 011202. [CrossRef]
Ali, M. S. , Tariq, A. , and Gandhi, B. K. , 2013, “ Flow and Heat Transfer Investigation Behind Trapezoidal Rib Using PIV and LCT Measurements,” Exp. Fluids, 54(5), p. 1520. [CrossRef]
Ali, M. S. , Tariq, A. , and Gandhi, B. K. , 2012, “ LCT and PIV Investigations Behind Trapezoidal-Rib With a Slit Mounted on Bottom Wall of a Rectangular Duct,” ASME Paper No. GTINDIA2012-9689.
Ali, M. S. , Tariq, A. , and Gandhi, B. K. , 2012, “ Detailed Investigation on Rib Turbulated Flow Inside a Rectangular Duct,” ASME Paper No. IMECE2012-87636.
Heidmann, J. D. , 1994, “ Determination of a Transient Heat Transfer Property of Acrylic Using Thermochromic Liquid Crystals,” NASA, Washington, DC, Technical Report No. NSN 7540-01-280-5500.
Ekkad, S. V. , and Han, J. C. , 2000, “ A Transient Liquid Crystal Thermography Technique for Gas Turbine Heat Transfer Measurements,” Meas. Sci. Technol., 11(7), pp. 957–968. [CrossRef]
Ireland, P. T. , and Jones, T. V. , 2000, “ Liquid Crystal Measurements of Heat Transfer and Surface Shear Stress,” Meas. Sci. Technol., 11(7), pp. 969–986. [CrossRef]
Chyu, M. K. , Ding, H. , Downs, J. P. , and Soechting, F. O. , 1998, “ Determination of Local Heat Transfer Coefficient Based on Bulk Mean Temperature Using a Transient Liquid Crystals Technique,” Exp. Therm. Fluid Sci., 18(2), pp. 142–149. [CrossRef]
Smith, A. R. , 1978, “ Color Gamut Transform Pairs,” 5th Annual Conference on Computer Graphics and Interactive Techniques, Bowling Green, OH, Aug. 23–25, pp. 12–19.
Tariq, A. , Singh, K. , and Panigrahi, P. K. , 2003 “ Flow and Heat Transfer in Rectangular Duct With Single Rib and Two Ribs Mounted on the Bottom Surface,” J. Enhanced Heat Transfer, 10(1), pp. 171–198. [CrossRef]
Keane, R. D. , and Adrian, R. J. , 1990, “ Optimization of Particle Image Velocimeters: Part I. Double-Pulsed System,” Meas. Sci. Technol., 1(11), pp. 1202–1215. [CrossRef]
Keane, R. D. , and Adrian, R. J. , 1991, “ Optimization of Particle Image Velocimeters: Part II. Multiple-Pulsed Systems,” Meas. Sci. Technol., 2(10), pp. 963–974. [CrossRef]
Kline, S. J. , and McClintock, F. A. , 1953, “ Describing Uncertainties in Single Sample Experiments,” J. Mech. Eng., 75, pp. 3–8.
Westerweel, J. , 1994, “ Efficient Detection of Spurious Vectors in Particle Image Velocimetry Data Sets,” Exp. Fluids, 16(3), pp. 236–247.
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 Degree Ribbed Walls,” Int. J. Heat Mass Transfer, 45(24), pp. 4809–4822. [CrossRef]
Kolar, V. , 1991, “ On the Critical Points in the Description of Vortical Flows,” Acta Mech., 89(1), pp. 241–245. [CrossRef]
Perry, A. E. , and Chong, M. S. , 1987, “ A Description of Eddying Motions and Flow Patterns Using Critical-Point Concepts,” Ann. Rev. Fluid Mech., 19(1), pp. 125–155. [CrossRef]
Hunt, J. C. R. , Abell, C. J. , Peterka, J. A. , and Woo, H. , 1978, “ Kinematics Studies of the Flows Around Free or Surface-Mounted Obstacles, Applying Topology to Flow Visualization,” J. Fluid Mech., 86(Pt. 1), pp. 179–200. [CrossRef]

Figures

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Fig. 1

Complete experimental facility for PIV and LCT measurements along with the details of rib configuration and heating section

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Fig. 4

Distribution of time-averaged normalized v-velocity (v/Ur) behind solid and slitted trapezoidal ribs at the lowest and the highest Reynolds numbers under investigation

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Fig. 3

Distribution of time-averaged normalized velocity magnitude (U/Ur) with stream traces behind solid and slitted trapezoidal ribs at the lowest and the highest Reynolds numbers under investigation

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Fig. 2

Comparison of span-averaged augmentation Nusselt number variation behind solid and slitted trapezoidal rib for varying chamfering angle at different Reynolds numbers

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Fig. 5

Close-up view of normalized velocity magnitude (U/Ur) with stream traces behind slitted trapezoidal ribs at different Reynolds numbers under investigation

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Fig. 6

Normalized stresses distribution and turbulent kinetic energy fluctuation field behind a solid and slitted trapezoidal ribs of varying chamfering angle at a typical Reynolds number of Re = 44,600

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Fig. 7

Normalized Reynolds stress distribution behind a solid and slitted trapezoidal ribs of varying chamfering angle at a typical Reynolds number of Re = 44,600

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Fig. 8

Instantaneous velocity vectors and corresponding vorticity distributions behind slitted trapezoidal ribs of varying chamfering angle at a typical Reynolds number of Re = 44,600

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Fig. 9

Normalized z-vorticity distribution behind solid and slitted ribs of varying chamfering angle at a typical Reynolds number of Re = 44,600

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Fig. 10

Surface augmentation Nusselt number distribution behind slitted trapezoidal ribs of varying chamfering angle at different Reynolds numbers

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