Skip to main content

Experimental Investigation of Natural Convection Heat Transfer in Heated Vertical Tubes with Discrete Rings

Experimental Techniques volume 41, pages 585–603 (2017)Cite this article

Abstract

Natural convection heat transfer from heated vertical pipes has been investigated experimentally. The pipes are open-ended and circular in cross section. The test sections are electrically heated imposing the circumferentially and axially constant wall heat flux. The outer surface of the test section is insulated and heat is allowed to dissipate from the internal surface. Experiments are carried out for four different channels of 45 mm internal diameter and 3.8 mm thickness with length varying from 450 mm to 850 mm. Ratios of length to diameter of the channel are taken as L/D = 10, 12.22, 15.56, and 18.89. Wall heat fluxes are maintained at q// = 250 to 3341 W/m2. Experiments are also carried out on intensified tubes of the same geometrical sizes with the discrete rings of rectangular cross section provided on the internal surface. Thickness of the rings are taken as t = 4, 6 and 8 mm; step size (s) of the rings are varying from 75 mm to 283.3 mm and the other ratios are taken as s/D = 1.67 to 6.29, t/D = 0.088 to 0.178 and s / t = 9.38 to 70.82. The effects of L/D ratio, ring thickness, ring spacing and wall heating conditions on local steady-state heat transfer phenomena are studied. A correlation is developed for average Nusselt number and modified Rayleigh number and another correlation is also developed for modified Rayleigh number and modified Reynolds number. These correlations predict the data accurately within ±10% error.

This is a preview of subscription content, access via your institution.

Access options

Buy single article

Instant access to the full article PDF.

USD 39.95

Price includes VAT (USA)
Tax calculation will be finalised during checkout.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

References

  1. Tanda G (1993) Natural convection heat transfer from a staggered vertical plate Array. J Heat Transf 115:938–945

    Article  Google Scholar 

  2. Sparrow EM, Prakash C (1980) Enhancement of natural convection heat transfer by a staggered Array of discrete vertical plates. ASME J Heat Transf 102:215–220

    Article  Google Scholar 

  3. Anug W, Beith KI, Kessler TJ (1972) Natural convection cooling of electronic cabinets containing arrays of vertical circuit cards. ASME Paper No.72-WA/HT-40, 26–30

  4. Capobianchi M, Aziz A (2012) A scale analysis for natural convective flows over vertical surfaces. Int J Therm Sci 54:82–88

    Article  Google Scholar 

  5. Jha BK, Ajibade AO (2012) Effect of viscous dissipation on natural convection flow between vertical parallel plates with time-periodic boundary conditions. Commun Nonlinear Sci Numer Simul 17:1576–1587

    Article  Google Scholar 

  6. Eckert ERG, Soehngen E (1951) Interferometric studies on the stability and transition to turbulence of a free convection boundary layer. Heat Transfer ASME-IME. London, 321–323

  7. Elenbaas W (1942) Heat dissipation of parallel plates by free convection. Physica 9:1–28

    Article  Google Scholar 

  8. Sernas V, Fletcher LS, Aung W (1972) Heat transfer measurements with a Wallaston prism Schlieren interferometer. ASME Paper No.72-HT-9, Presented at the AIChE-ASME Heat Transfer Conf, Denver, 6–9

  9. Sparrow EM, Bahrami PA (1980) Experiments in natural convection from vertical parallel plates with either open or closed edges. ASME J Heat Transf 102:221–227

    Article  Google Scholar 

  10. Akbari H, Borges TR (1979) Free convective laminar flow within Trombe wall channel. Sol Energy 22:165–174

    Article  Google Scholar 

  11. Tichy JA (1983) The effect of inlet and exit losses on free convective laminar flow in the Trombe Wall channel. J Sol Energy Eng 105(2):187–193

    Article  Google Scholar 

  12. Levy EK, Eichen PA, Cintani WR, Shaw RR (1975) Optimum plate spacing for laminar natural convection heat transfer from parallel vertical isothermal flat plates, experimental verification. ASME J Heat Transfer 97:474–476

    Article  Google Scholar 

  13. Sankar M, Park Y, Lopez JM, Do Y (2011) Numerical study of natural convection in a vertical porous annulus with discrete heating. Int J Heat Mass Transf 54:1493–1505

    Article  Google Scholar 

  14. Du DX, Tian WX, Su GH, Qiu SZ, Huang YP, Yan X (2012) Theoretical study on the characteristics of critical heat flux in vertical narrow rectangular channels. Appl Therm Eng 36:21–31

    Article  Google Scholar 

  15. Kang GU, Chung BJ (2010) The experimental study on transition criteria of natural convection inside a vertical pipe. Int Commun Heat Mass Transfer 37:1057–1063

    Article  Google Scholar 

  16. Dey S, Chakrborty D (2009) Enhancement of convective cooling using oscillating fins. Int Commun Heat Mass Transfer 36:508–512

    Article  Google Scholar 

  17. Buonomo B, Manca O (2010) Natural convection slip flow in a vertical micro channel heated at uniform heat flux. Int J Therm Sci 49:1333–1344

    Article  Google Scholar 

  18. Morshedy SEE, Alyan A, Shouman L (2012) Experimental investigation of natural convection heat transfer in narrow vertical rectangular channel heated from both sides. Exp Thermal Fluid Sci 36:72–77

    Article  Google Scholar 

  19. Nayak RC, Roul MK, Sarangi SK (2017) Experimental investigation of natural convection heat transfer in heated vertical tubes. Int J Appl Eng Res 12:2538–2550

    Google Scholar 

  20. Vliet GC (1969) Natural convection local heat transfer on constant-heat-flux inclined surfaces. J Heat Transf 91:511–516

    Article  Google Scholar 

  21. Churchill SW, Chu HHS (1975) Correlating equations for laminar and turbulent free convection from a vertical plate. Int J Heat Mass Transf 18:1323–1329

    Article  Google Scholar 

  22. Gbadebo SA, Said SAM, Habib MA (1999) Average Nusselt number correlation in the thermal entrance region of steady and pulsating turbulent pipe flows. Heat Mass Transf 35:377–381

    Article  Google Scholar 

  23. Hernandez J, Zamora B (2005) Effects of variable properties and non-uniform heating on natural convection flows in vertical channels. Int J Heat Mass Transf 48:793–807

    Article  Google Scholar 

  24. Velmurugan P, Kalaivanan R (2016) Energy and exergy analysis in double-pass solar air heater. Sadhana 41:369–376

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Mechanical Engineering, SOA University, Bhubaneswar, PIN-751030, India

    R. C. Nayak & S. K. Sarangi

  2. Department of Mechanical Engineering, GITA, Bhubaneswar, Odisha, PIN-752054, India

    M. K. Roul

Authors
  1. R. C. Nayak
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. K. Roul
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. S. K. Sarangi
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to R. C. Nayak.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Nayak, R.C., Roul, M.K. & Sarangi, S.K. Experimental Investigation of Natural Convection Heat Transfer in Heated Vertical Tubes with Discrete Rings. Exp Tech 41, 585–603 (2017). https://doi.org/10.1007/s40799-017-0201-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40799-017-0201-6

Keywords

  • Heat flux
  • Heat transfer
  • Natural convection
  • Ring spacing
  • Ring thickness
  • Correlation