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Research Papers: Forced Convection

Effect of Rounded Corners on Heat Transfer and Fluid Flow Through Triangular Duct

[+] Author and Article Information
Rajneesh Kumar

Mechanical Engineering Department,
National Institute of Technology,
Hamirpur 177005, India
e-mail: rajneesh127.nith@gmail.com

Anoop Kumar

Professor
Mechanical Engineering Department,
National Institute of Technology,
Hamirpur 177005, India
e-mail: anoop@nith.ac.in

Varun Goel

Mechanical Engineering Department,
National Institute of Technology,
Hamirpur 177005, India
e-mail: varun7go@gmail.com

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received January 24, 2018; final manuscript received July 13, 2018; published online August 28, 2018. Assoc. Editor: Danesh K. Tafti.

J. Heat Transfer 140(12), 121701 (Aug 28, 2018) (10 pages) Paper No: HT-18-1048; doi: 10.1115/1.4040957 History: Received January 24, 2018; Revised July 13, 2018

Turbulent flow heat transfer and friction penalty in triangular cross-sectional duct is studied in the present paper. The sharp corners of the duct are modified by converting it into circular shape. Five different models were designed and fabricated. Heat transfer through all the models was investigated and compared conventional triangular duct under similar conditions. The curvature radius of rounded corners for different models was kept constant (0.33 times the duct height). The numerical simulations were also performed and the obtained result validated with the experimental findings and close match observed between them. The velocity and temperature distribution is analyzed at particular location in the different models. Because of rounded corners, higher velocity is observed inside the duct (except corners) compared to conventional duct. Considerable increase in Nusselt number is seen in model-5, model-4, model-3, and model-2 by 191%, 41%, 19%, and 8% in comparison to model-1, respectively, at higher Reynolds number (i.e., 17,500). But, frictional penalty through the model-5, model-4, model-3, and model-2 increased by 287%, 54%, 18%, and 12%, respectively, in comparison to model-1 at lower Reynolds number (i.e., 3600).

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References

Bharadwaj, G. , Kaushal, M. , and Goel, V. , 2013, “ Heat Transfer and Friction Characteristics of an Equilateral Triangular Solar Air Heater Duct Using Inclined Continuous Ribs as Roughness Element on the Absorber Plate,” Int. J. Sustainable Energy, 32(6), pp. 515–530. [CrossRef]
Das, D. , and Basak, T. , 2016, “ Role of Distributed/Discrete Solar Heaters During Natural Convection in the Square and Triangular Cavities: CFD and Heatline Simulations,” Sol. Energy, 135, pp. 130–153. [CrossRef]
Kumar, R. , Kumar, A. , and Varun , 2017, “ Computational Fluid Dynamics Based Study for Analyzing Heat Transfer and Friction Factor in Semi-Circular Rib Roughened Equilateral Triangular Duct,” Int. J. Numer. Methods Heat Fluid Flow, 27(4), pp. 941–957.
Zhang, L. Z. , 2005, “ Turbulent Three-Dimensional Air Flow and Heat Transfer in a Cross-Corrugated Triangular Duct,” ASME J. Heat Transfer, 127(10), pp. 1151–1158. [CrossRef]
Braga, S. L. , and Saboya, F. E. M. , 1996, “ Turbulent Heat Transfer and Pressure Drop in an Internally Finned Equilateral Triangular Duct,” Exp. Therm. Fluid Sci., 12(1), pp. 57–64. [CrossRef]
Amro, M. , Weigand, B. , Poser, R. , and Schnieder, M. , 2007, “ An Experimental Investigation of the Heat Transfer in Ribbed Triangular Cooling Channel,” Int. J. Therm. Sci., 46(5), pp. 491–500. [CrossRef]
Cebeci, T. , and Bradshaw, P. , 1988, Physical and Computational Aspects of Convective Heat Transfer, Springer-Verlag, Germany, pp. 130–140.
Eckert, E. R. G. , and Low, G. M. , 1951, “ Temperature Distribution in Internally Heated Walls of Heat Exchangers Composed of Non-Circular Flow Passages,” National Advisory Committee for Aeronautics, Cleveland, OH, Technical Report No. NACA-TR-1022. https://ntrs.nasa.gov/search.jsp?R=19930092077
Obot, N. T. , Esen, E. B. , and Adu-Wusu, K. , 1987, “ Pressure Drop for Rib-Roughened Scalene Triangular Duct Having Two Rounded Corners,” Int. Commun. Heat Mass Transfer, 14(1), pp. 11–20. [CrossRef]
Leung, C. W. , Wong, T. T. , and Probert, S. D. , 2001, “ Enhanced Forced-Convection From Ribbed or Machine-Roughened Inner Surfaces Within Triangular Ducts,” Appl. Energy, 69(2), pp. 87–99. [CrossRef]
Luo, D. D. , 2006, “ Forced Convection and Fluid Friction in a Horizontal Triangular Duct With Uniformly Ribbed or Grooved Internal Surfaces,” Ph. D. thesis, The Hong Kong Polytechnic University, Hung Hom, China.
Nan, S. F. , and Dou, M. , 2000, “ A Method of Correlating Fully Developed Turbulent Friction in Triangular Ducts,” ASME J. Fluids Eng., 122(3), pp. 634–636. [CrossRef]
He, S. , and Gotts, J. A. , 2004, “ Calculation of Friction Coefficients for Noncircular Channels,” ASME J. Fluids Eng., 126(6), pp. 1033–1038. [CrossRef]
Shahmardan, M. M. , Sedaghat, M. H. , and Norouzi, M. , 2014, “ An Analytical Solution for Fully Developed Forced Convection in Triangular Ducts,” Heat Transfer-Asian Res., 44(6), pp. 489–498. [CrossRef]
Wang, C. Y. , 2014, “ H2 Forced Convection for Slip Flow in an Equilateral Triangular Duct,” J. Thermophys. Heat Transfer, 28(1), pp. 100–104. [CrossRef]
Karabulut, H. , Ipci, D. , and Cinar, C. , 2016, “ Numerical Solution of Fully Developed Heat Transfer Problem With Constant Wall Temperature and Application to Isosceles Triangular and Parabolic Ducts,” Appl. Therm. Eng., 102, pp. 115–124. [CrossRef]
Kumar, R. V. , and Kumar, A. , 2016, “ Thermal and Fluid Dynamic Characteristics of Flow Through Triangular Cross-Sectional Duct: A Review,” Renewable Sustainable Energy Rev., 61, pp. 123–140. [CrossRef]
Shah, R. K. , 1975, “ Laminar Flow Friction and Forced Convection Heat Transfer in Duct of Arbitrary Geometry,” Int. J. Heat Mass Transfer, 18(7–8), pp. 849–862. [CrossRef]
Chen, S. , Chan, T. L. , Leung, C. W. , and Yu, B. , 2000, “ Numerical Prediction of Laminar Forced Convection in Triangular Ducts With Unstructured Triangular Grid Method,” Numer. Heat Transfer, Part A, 38, pp. 209–224. [CrossRef]
Leung, C. W. , Wong, T. T. , and Kang, H. J. , 1998, “ Forced Convection of Turbulent Flow in Triangular Ducts With Different Angles and Surface Roughnesses,” Heat Mass Transfer, 34(1), pp. 63–68. [CrossRef]
Uzun, I. , and Unsal, M. , 1997, “ A Numerical Study of Laminar Heat Convection in Ducts of Irregular Cross-Sections,” Int. Commun. Heat Mass Transfer, 24(6), pp. 835–848. [CrossRef]
Mortazavi, S. N. , and Hassanipour, F. , 2014, “ Effect of Apex Angle, Porosity, and Permeability on Flow and Heat Transfer in Triangular Porous Ducts,” ASME J. Heat Transfer, 136(11), p. 112602. [CrossRef]
Obot, N. T. , and Adu-Wusu, K. , 1985, “ The Flow Pattern in a Scalene Triangular Duct Having Two Rounded Corners,” ASME J. Fluids Eng., 107(4), pp. 455–459. [CrossRef]
Ray, S. , and Misra, D. , 2010, “ Laminar Fully Developed Flow Through Square and Equilateral Triangular Ducts With Rounded Corners Subjected to H1 and H2 Boundary Conditions,” Int. J. Therm. Sci., 49(9), pp. 1763–1775. [CrossRef]
Tu, J. , Yeoh, G. H. , and Liu, C. , 2013, “Computational Fluid Dynamics: A Practical Approach,” 2nd ed., Butterworth-Heinemann, Elsevier, UK.
ANSYS, 2009, “ Fluent 12.1, 2003-04, Documentation,” ANSYS Inc., Canonsburg, PA.
Patankar, S. V. , 1980, Numerical Heat Transfer and Fluid Flow, Hemisphere, Washington, DC.
Ramirez-Minguela, J. J. , Alfaro-Ayala, J. A. , Rangel-Hernandez, V. H. , Uribe-Ramirez, A. R. , Mendoza-Miranda, J. M. , Perez-Garcia, V. , and Belman-Flores, J. M. , 2018, “ Comparison of the Thermo-Hydraulic Performance and the Entropy Generation Rate for Two Type of Low Temperature Solar Collector Using CFD,” Sol. Energy, 166, pp. 123–137. [CrossRef]
De Groot, S. R. , and Mazur, P. , 2011, Non-Equilibrium Thermodynamics, Dover Publications, New York.
Bejan, A. , Tsatsaronis, G. , and Moran, M. , 1996, Thermal Design and Optimization, Wiley, Hoboken, NJ.
Daschiel, G. , Frohnapfel, B. , and Jovanovic, J. , 2013, “ Numerical Investigation of flow Through a Triangular Duct: The Coexistence of Laminar and Turbulent flow,” Int. J. Heat Fluid Flow, 41, pp. 27–33. [CrossRef]
Eckert, E. , and Irvine, T. , 1956, “ Flow in Corners of Passages With Non-Circular Cross-Sections,” Trans. ASME, 78(4), pp. 709–718.
Rao, Y. , Feng, Y. , Li, B. , and Weigand, B. , 2015, “ Experimental and Numerical Study of Heat Transfer and Flow Friction in Channels With Dimples of Different Shapes,” ASME J. Heat Transfer, 137(3), p. 031901. [CrossRef]
Kumar, R. , Kumar, A. , and Goel, V. , 2016, “ Numerical Simulation of Flow Through Equilateral Triangular Duct Under Constant Wall Heat Flux Boundary Condition,” J. Inst. Eng. (India): Ser. C, 98(3), pp. 313–323. [CrossRef]
Sato, N. , Inagaki, M. , Kaneda, K. , Horinouchi, N. , and Ota, A. , 2017, “ Numerical Investigation of the Effect of Prandtl Number on Heat Transfer in a Dimpled-Channel Flow,” Int. J. Heat Fluid Flow, 68, pp. 139–150. [CrossRef]
Kumar, R. , Goel, V. , and Kumar, A. , 2018, “ Investigation of Heat Transfer Augmentation and Friction Factor in Triangular Duct Solar Air Heater Due to Forward Facing Chamfered Rectangular Ribs: A CFD Based Analysis,” Renewable Energy, 115, pp. 824–835. [CrossRef]
Bhardwaj, S. , Dalal, A. , and Pati, S. , 2015, “ Influence of Wavy Wall and Non-Uniform Heating on Natural Convection Heat Transfer and Entropy Generation Inside Porous Complex Enclosure,” Energy, 79, pp. 467–481. [CrossRef]
Ligrani, P. M. , Harrison, J. L. , Mahmood, G. L. , and Hill, M. L. , 2001, “ Flow Structure Due to Dimple Depression on a Channel Surface,” Physic Fluids, 13(11), pp. 3442–3451. [CrossRef]

Figures

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Fig. 4

Location of thermocouples placed on heat conducting side of the duct

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Fig. 3

Pictorial view of dimple-shaped protruded heat conducting side

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Fig. 2

Schematic view of different models examined in present work. (a) Model 1 (simple triangular duct), (b) Model 2 (triangular duct with one rounded corner), (c) Model 3 (triangular duct with two rounded corners), (d) Model 4 (triangular duct with three rounded corners), and (e) Model 5 (all corners are rounded and roughness on the heat conducting side of the duct).

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Fig. 1

Schematic flow diagram of experimental setup

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Fig. 5

Geometry with symmetry about a plane

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Fig. 6

Schematic of designed geometry with boundary conditions for performing simulations in case of the model 5

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Fig. 7

Meshed computational domain with inflation

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Fig. 8

Variation of dimensionless velocity in the duct at axial length of z/ltest = 0.75

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Fig. 14

Variation of f with Re for different x/e values

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Fig. 9

Variation of dimensionless temperature in the duct at axial length of z/ltest = 0.75

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Fig. 10

Variation of Nuavg with Re in different models

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Fig. 11

Variation of f with Re for different models

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Fig. 12

Variation of sgen with Re for different models

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Fig. 13

Variation of Nu with Re for different x/e values

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