Research Papers: Heat Exchangers

The Correlation of Heat Transfer Coefficients for the Laminar Natural Convection in a Circular Finned-Tube Heat Exchanger

[+] Author and Article Information
Hie Chan Kang

School of Mechanical and
Automotive Engineering,
Kunsan National University,
558 Daehak-ro,
Gunsan-shi 54150, Jeollabuk-do, South Korea

Se-Myong Chang

School of Mechanical and
Automotive Engineering,
Kunsan National University,
558 Daehak-ro,
Gunsan-shi 54150, Jeollabuk-do, South Korea
e-mail: smchang@kunsan.ac.kr

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received May 10, 2016; final manuscript received August 16, 2017; published online December 6, 2017. Assoc. Editor: P. K. Das.

J. Heat Transfer 140(3), 031801 (Dec 06, 2017) (10 pages) Paper No: HT-16-1264; doi: 10.1115/1.4038189 History: Received May 10, 2016; Revised August 16, 2017

This study proposes an empirical correlation for laminar natural convection applicable to external circular finned-tube heat exchangers with wide range of configuration parameters. The transient temperature response of the heat exchangers was used to obtain the heat transfer coefficient, and the experimental data with their characteristic lengths are discussed. The data lie in the range from 1 to 1000 for Rayleigh numbers based on the fin spacing: the ratio of fin height to tube diameter ranges from 0.1 to 0.9, and the ratio of fin pitch to height ranges from 0.13 to 2.6. Sixteen sets of finned-tube electroplated with nickel–chrome were tested. The convective heat transfer coefficients on the heat exchangers were measured by elimination of the thermal radiation effect from the heat exchanger surfaces. The Nusselt number was correlated with a newly suggested composite curve formula, which converges to the quarter power of the Rayleigh number for a single cylinder case. The proposed characteristic length for the Rayleigh number is the fin pitch while that for the Nusselt number is mean flow length, defined as half the perimeter of the mean radial position inside the flow region bounded by the tube surface and two adjacent fins. The flow is regarded as laminar, which covers heat exchangers from a single horizontal cylinder to infinite parallel disks. Consequently, the result of curve fitting for the experimental data shows the reasonable physical interpretation as well as the good quantitative agreement with the correction factors.

Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.


Morgan, V. T. , 1975, “ The Overall Convective Heat Transfer From Smooth Circular Cylinders,” Advances in Heat Transfer, T. F. Irvine and J. P. Hartnett , eds., Academic Press, New York, pp. 199–269. [CrossRef]
Yovanovich, M. M. , 1988, “ On the Effect of Shape, Aspect Ratio and Orientation Upon Natural Convection From Isothermal Bodies of Complex Shape,” ASME National Heat Transfer Conference, Houston, TX, July 24–27, pp. 121–129. http://www.mhtl.uwaterloo.ca/pdf_papers/mhtl87-8.pdf
Wang, C. S. , Yovanovich, M. M. , and Culham, J. R. , 1999, “ Modeling Natural Convection From Horizontal Isothermal Annular Heat Sinks,” ASME J. Electron. Packag., 121(1), pp. 44–49. [CrossRef]
Kayansayan, N. , 1993, “ Thermal Characteristics of Fin-and-Tube Heat Exchanger Cooled by Natural Convection,” Exp. Therm. Fluid Sci., 7(3), pp. 177–188. [CrossRef]
Merk, H. J. , and Prins, J. A. , 1954, “ Thermal Convection Laminar Boundary Layer III,” Appl. Sci. Res., 4(3), pp. 207–221. [CrossRef]
Lienhard, J. H. , 1973, “ On the Commonality of Equations for Natural Convection From Immersed Bodies,” Int. J. Heat Mass Transfer, 16(11), pp. 2121–2123. [CrossRef]
Churchill, S. W. , and Chu, H. H. S. , 1975, “ Correlating Equations for Laminar and Turbulent Free Convection From a Vertical Plate,” Int. J. Heat Mass Transfer, 18(11), pp. 1323–1329. [CrossRef]
Elenbaas, W. , 1942, “ Heat Dissipation of Parallel Plates by Free Convection,” Phys., 9(1), pp. 1–28.
Martin, L. , Raithby, G. D. , and Yovanovich, M. M. , 1991, “ On the Low Rayleigh Number Convection Through an Isothermal, Parallel-Plate Channel,” ASME J. Heat Transfer, 113(4), pp. 899–905. [CrossRef]
Vorayos, N. , 2000, “ Laminar Natural Convection Within Long Vertical Uniformly Heated Parallel-Plate Channels and Circular Tubes,” Ph.D. thesis, Oregon State University, Corvallis, OR. http://ir.library.oregonstate.edu/xmlui/handle/1957/32600
Kang, H. C. , and Jang, H. S. , 2011, “ Natural Convection Correlations of Circular Finned Tube Heat Exchanger,” ASME Paper No. AJK2011-35012.
JSME, 1986, Heat Transfer Engineering Data, 4th ed., JSME, Tokyo, Japan.
Bhuiyan, A. A. , and Sadrul Islam, A. K. M. , 2016, “ Thermal and Hydraulic Performance of Finned-Tube Heat Exchangers Under Different Flow Ranges: A Review on Modeling and Experiment,” Int. J. Heat Mass Transfer, 101, pp. 38–59. [CrossRef]
Abdelmessih, A. , and Bell, K. , 1999, “ Effect of Mixed Convection and U-Bends on the Design of Double Pipe Heat Exchangers,” Heat Transfer Eng., 20(3), pp. 25–36. [CrossRef]
Siegel, R. , and Howell, J. R. , 1992, Thermal Radiation Heat Transfer, 3rd ed., McGraw-Hill, New York, p. 1042.
Jafarpur, K. , and Yovanovich, M. M. , 1992, “ Laminar Free Convective Heat Transfer From Isothermal Spheres: A New Analytical Method,” Int. J. Heat Mass Transfer, 35(9), pp. 2195–2201. [CrossRef]


Grahic Jump Location
Fig. 1

Schematic of the present experimental model with symbols for dimension

Grahic Jump Location
Fig. 2

Setups of apparatus for the present experiment

Grahic Jump Location
Fig. 3

Primary regime between two extreme conditions for natural convection in the circular fin-tube configuration

Grahic Jump Location
Fig. 5

Plot of experimental data for the sixteen cases of circular fin-tube configurations

Grahic Jump Location
Fig. 4

Plot of correlations of natural convection around a horizontal cylinder, extreme condition of s/Di=0.187 and C = 0.436 in classical theories

Grahic Jump Location
Fig. 6

Linear regression of experimental data for D22 cases [11]

Grahic Jump Location
Fig. 9

Results of the full correlation: (a) D12, (b) D18, and (c) D28 cases

Grahic Jump Location
Fig. 10

The correction factor to related the correlation with experimental data

Grahic Jump Location
Fig. 7

Results of the reduced correlation, Eq. (46) with experimental result: (a) D12, (b) D18, (c) D22, and (d) D28

Grahic Jump Location
Fig. 8

Results of the full correlation, D22 cases: (a) before and (b) after the correction




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In