0
Research Papers: Natural and Mixed Convection

An Experimental Study of Mixed Convection in Vertical, Open-Ended, Concentric and Eccentric Annular Channels

[+] Author and Article Information
S. Tavoularis

e-mail: stavros.tavoularis@uottawa.ca
Department of Mechanical Engineering,
University of Ottawa,
161 Louis Pasteur,
Ottawa, Ontario K1N 6N5, Canada

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received August 5, 2012; final manuscript received February 18, 2013; published online June 17, 2013. Assoc. Editor: Ali Ebadian.

J. Heat Transfer 135(7), 072502 (Jun 17, 2013) (9 pages) Paper No: HT-12-1418; doi: 10.1115/1.4023748 History: Received August 05, 2012; Revised February 18, 2013

The effect of eccentricity on heat transfer in upward flow in a vertical, open-ended, annular channel with a diameter ratio of 0.61, an aspect ratio of 18:1, and both internal surfaces heated uniformly has been investigated experimentally. Results have been reported for eccentricities ranging from the concentric case to the near-contact case and three inlet bulk Reynolds numbers, equal approximately to 1500, 2800, and 5700. This work complements our recently reported experimental results on natural convection in the same facility. The present results are deemed to be largely in the mixed convection regime with some overlap with the forced convection regime and likely to include cases with laminar, transitional, and turbulent flows in at least a part of the test section. Small eccentricity had an essentially negligible effect on the overall heat transfer rate, but high eccentricity reduced the average heat transfer rate by up to 60%. High eccentricity also resulted in wall temperatures in the narrow gap region that were much higher than those in the open channel. The concentric-case Nusselt number was higher than the Dittus–Boelter prediction, whereas the highly eccentric-case Nusselt number was significantly lower than that.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Jackson, J. D., and Hall, W. B., 1979, “Influences of Buoyancy on Heat Transfer to Fluids Flowing in Vertical Tubes Under Turbulent Conditions,” Turbulent Forced Convection in Channels and Bundles, Vol. 2, Kakaç, S., and Spalding, D. B., eds., Hemisphere, WA, pp. 613–640.
Jackson, J. D., Cotton, M. A., and Axcell, B. P., 1989, “Studies of Mixed Convection in Vertical Tubes,” Int. J. Heat Fluid Flow, 10(1), pp. 2–15. [CrossRef]
Tavoularis, S., 2011, “Rod Bundle Vortex Networks, Gap Vortex Streets, and Gap Instability: A Nomenclature and Some Comments on Available Methodologies,” Nucl. Eng. Des., 241(7), pp. 2624–2626. [CrossRef]
Piot, E., and Tavoularis, S., 2011, “Gap Instability of Laminar Flows in Eccentric Annular Channels,” Nucl. Eng. Des., 241(11), pp. 4615–4620. [CrossRef]
Meyer, L., 2010, “From Discovery to Recognition of Periodic Large Scale Vortices in Rod Bundles as Source of Natural Mixing Between Subchannels—A Review,” Nucl. Eng. Des., 240, pp. 1575–1588. [CrossRef]
Merzari, E., Wang, S., Ninokata, H., and Theofilis, V., 2008, “Biglobal Linear Stability Analysis for the Flow in Eccentric Annular Channels and a Related Geometry,” Phys. Fluids, 20, p. 114104-1–114104-13. [CrossRef]
Merzari, E., and Ninokata, H., 2009, “Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels,” Flow Turbul. Combust., 82, pp. 93–120. [CrossRef]
Ninokata, H., Merzari, E., and Khakim, A., 2009, “Analysis of Low Reynolds Number Turbulent Flow Phenomena in Nuclear Fuel Pin Subassemblies of Tight Lattice Configuration,” Nucl. Eng. Des., 239, pp. 855–866. [CrossRef]
Dalle Donne, M., and Meerwald, E., 1973, “Heat Transfer and Friction Coefficients for Turbulent Flow of Air in Smooth Annuli at High Temperatures,” Int. J. Heat Mass Transfer, 16, pp. 787–809. [CrossRef]
Childs, P. R. N., and Long, C. A., 1996, “A Review of Forced Convective Heat Transfer in Stationary and Rotating Annuli,” Proc. Inst. Mech. Eng., 210, pp. 123–134. [CrossRef]
El-Genk, M. S., and Rao, D. V., 1990, “Buoyancy Induced Instability of Laminar Flows in Vertical Annuli—I Flow Visualization and Heat Transfer Experiments,” Int. J. Heat Mass Transfer, 33, pp. 2145–2159. [CrossRef]
Hasan, A., Roy, R. P., and Kalra, S. P., 1992, “Velocity and Temperature Fields in Turbulent Liquid Flow Through a Vertical Concentric Annular Channel,” Int. J. Heat Mass Transfer, 35, pp. 1455–1467. [CrossRef]
Kang, S., Patil, B., Zarate, J. A., and Roy, R. P., 2001, “Isothermal and Heated Turbulent Upflow in a Vertical Annular Channel—Part I: Experimental Measurements,” Int. J. Heat Mass Transfer, 44, pp. 1171–1184. [CrossRef]
Yu, B., Kawaguchi, Y., Kaneda, M., Ozoe, H., and Churchill, S. W., 2005, “The Computed Characteristics of Turbulent Flow and Convection in Concentric Circular Annuli—Part II: Uniform Heating on the Inner Surface,” Int. J. Heat Mass Transfer, 48, pp. 621–634. [CrossRef]
Yu, B., Kawaguchi, Y. M., Ozoe, H., and Churchill, S. W., 2005, “The Computed Characteristics of Turbulent Flow and Convection in Concentric Circular Annuli—Part III: Alternative Thermal Boundary Conditions,” Int. J. Heat Mass Transfer, 48, pp. 635–646. [CrossRef]
Chung, S. Y., and Sung, H. J., 2003, “Direct Numerical Simulation of Turbulent Concentric Annular Pipe Flow—Part II: Heat Transfer,” Int. J. Heat Fluid Flow, 24, pp. 399–411. [CrossRef]
Ould-Rouiss, M., Redjem-Saad, L., and Lauriat, G., 2009, “Direct Numerical Simulation of Turbulent Heat Transfer in Annuli: Effect of Heat Flux Ratio,” Int. J. Heat Fluid Flow, 30, pp. 579–589. [CrossRef]
Lee, J. S., Xu, X., and Pletcher, R. H., 2004, “Large Eddy Simulation of Heated Vertical Annular Pipe Flow in Fully Developed Turbulent Mixed Convection,” Int. J. Heat Mass Transfer, 47, pp. 437–446. [CrossRef]
Sun, Z. N., Yan, C. Q., Tan, H. P., Guo, J. Q., and Sun, L. C., 2002, “Forced Convection Heat Transfer in Narrow Annulus With Bilateral Heating,” Nucl. Power Eng., 23(4), pp. 33–36.
Zeng, H. Y., Qiu, S. Z., and Jia, D. N., 2007, “Investigation of the Characteristics of the Flow and Heat Transfer in Bilaterally Heated Narrow Annuli,” Int. J. Heat Mass Transfer, 50, pp. 492–501. [CrossRef]
Manglik, R. M., and Fang, P. P., 1995, “Effect of Eccentricity and Thermal Boundary Conditions on Laminar Fully Developed Flow in Annular Ducts,” Int. J. Heat Fluid Flow, 16, pp. 298–306. [CrossRef]
Mokheimer, E. M. A., and El-Shaarawi, M. A. I., 2004a, “Developing Mixed Convection in Vertical Eccentric Annuli,” Heat Mass Transfer, 41, pp. 176–187. [CrossRef]
Mokheimer, E. M. A., and El-Shaarawi, M. A. I., 2004b, “Critical Values of Gr/Re for Mixed Convection in Vertical Eccentric Annuli With Isothermal/Adiabatic Walls,” ASME J. Heat Transfer, 126, pp. 479–492. [CrossRef]
Choueiri, G. H., and Tavoularis, S., 2011, “An Experimental Study of Natural Convection in Vertical, Open-Ended, Concentric and Eccentric Annular Channels,” ASME J. Heat Transfer, 133(12), p. 122503-1–122503-9. [CrossRef]
Sparrow, E. M., Chrysler, G. M., and Azevedo, L. F., 1984, “Observed Flow Reversals and Measured-Predicted Nusselt Numbers for Natural Convection in a One-Sided Heated Vertical Channel,” ASME J. Heat Transfer, 106, pp. 325–332. [CrossRef]
Tavoularis, S., 2005, Measurement in Fluid Mechanics, Cambridge University Press, Cambridge, UK.
Incropera, F. P., and DeWitt, D. P., 2006, Introduction to Heat Transfer, Fifth ed., Wiley, Hoboken, NJ.
Dittus, F. W., and Boelter, L. M. K., 1930, “Heat Transfer in Automobile Radiators of the Tubular Type, UC Pub. Eng., 2, pp. 443–461. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Schematic diagram of the experimental apparatus

Grahic Jump Location
Fig. 2

Sketch of the annular duct cross section showing positions of thermocouples and foil gaps

Grahic Jump Location
Fig. 3

Representative wall temperature measurements along the annulus for different eccentricities; ○, ◇, and □ denote the readings of thermocouples S0i, S90i, and S180i, respectively, whereas +, ×, and are for the corresponding thermocouples on the outer cylinder; Re = 2800

Grahic Jump Location
Fig. 4

Azimuthal temperature variation for the inner (a) and outer (b) cylinders at z/H = 0.5; e = 0 (), 0.1 (□), 0.3 (×), 0.5 (+), 0.7 (◇), 0.8 (○) and 0.9 (♦); Re = 2800

Grahic Jump Location
Fig. 5

Azimuthally averaged temperature variation along the annulus for various eccentricities and Reynolds numbers (symbols are the same as in Fig. 4)

Grahic Jump Location
Fig. 6

Circumferentially averaged wall temperature rise at z/H = 0.5; □: Re = 1500, ▿: Re = 2800, ◇: Re = 5700; △: natural convection measurements by CT at Re ≈ 900. Smooth lines approaching constant asymptotes at e = 0 and 1 have been fitted to all data sets.

Grahic Jump Location
Fig. 7

Ratio of Richardson number to the Richardson number for natural convection at the same eccentricity for concentric (○) and highly eccentric (△; e = 0.9) annular channels at midheight

Grahic Jump Location
Fig. 8

Application of the Jackson and Hall criterion (dashed line) to test the influence of buoyancy forces on the heat transfer coefficient in concentric (●) and highly eccentric (▴; e = 0.9) annular channels at midheight; open symbols represent corresponding natural convection measurements by CT

Grahic Jump Location
Fig. 9

Azimuthal variation of the local Nusselt number for the inner (a) and outer (b) cylinders at z/H = 0.5; e = 0 (), 0.1 (□), 0.3 (×), 0.5 (+), 0.7 (◇), 0.8 (○) and 0.9 (♦); Re = 2800

Grahic Jump Location
Fig. 10

Azimuthally averaged Nusselt number versus eccentricity at z/H = 0.5, □; Re = 1500, ▿; Re = 2800, ◇; Re = 5700, △: natural convection measurements by CT at Re ≈ 900. Smooth lines approaching constant asymptotes at e = 0 and 1 have been fitted to all data sets; uncertainty bars have been drawn for the concentric case results, as representative of all results.

Grahic Jump Location
Fig. 11

Nusselt number versus Reynolds number at z/H = 0.5; closed symbols correspond to present results, whereas open symbols correspond to natural convection; circles denote concentric cases, whereas triangles denote highly eccentric (e = 0.9) cases; solid lines: exponential curves fitted to the present data; dashed line: laminar flow in pipes; dotted line: El-Genk and Rao correlation; dash and dot line: Dittus–Boelter correlation; uncertainty bars have been drawn for the concentric case results.

Tables

Errata

Discussions

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