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Heat transfer characteristics of water flowing through micro-tube heat exchanger with variable fluid properties

  • Rajan KumarEmail author
  • Shripad P. Mahulikar
Article
  • 17 Downloads

Abstract

The heat transfer characteristics of laminar single-phase forced convective water flow through a micro-tube heat exchanger are numerically investigated in this paper. Two-dimensional simulations are performed to find the effects of variable fluid properties on heat transfer for hydrodynamically and thermally developed flow. The effects of variable fluid properties on convective heat transfer coefficient (h) and Nusselt number (Nu) are significant for micro-convective flow. It is noted that the variation in temperature-dependent thermal conductivity [k(T)] greatly enhances the h as compared to the variation in temperature-dependent viscosity [µ(T)], although water viscosity–temperature sensitivity (SμT) is greater than that of thermal conductivity–temperature sensitivity (SkT). The effects of variation in wall heat flux (\(q_{\text{w}}^{\prime\prime}\)) and inlet temperature on heat transfer are investigated for variable fluid properties. It is noted that the Nu declines with an augment in \(q_{\text{w}}^{\prime\prime}\) for temperature-dependent density variation [ρ(T)]. The Nu increases with an increase in \(q_{\text{w}}^{\prime\prime}\) for µ(T) and k(T) variations. The results show that the Nu decreases with an increase in inlet temperature for variable fluid properties. The undevelopment and redevelopment of the flow are observed due to µ(T) variation. Additionally, the effects of wall heat flux, inlet temperature and inlet velocity on the variation of Nu/Pr1/3 with Re are examined for µ(T) variation.

Keywords

Micro-channel Fully developed flow Heat transfer Variable fluid properties Flow undevelopment 

List of symbols

A

Cross-sectional area of micro-tube (m2)

cp(T)

Temperature-dependent specific heat at constant pressure (J kg−1 K−1)

D

Diameter of micro-tube (m)

L

Length of micro-tube (m)

f

Friction factor

h

Convective heat transfer coefficient (W m−2 K−1)

k(T)

Temperature-dependent thermal conductivity (W m−1 K−1)

\(q_{\text{w}}^{\prime\prime}\)

Wall heat flux (W m−2)

Tm,in

Inlet temperature (K)

Tm

Bulk mean fluid temperature (K)

Tw

Wall temperature (K)

T(r)

Temperature profile in radial direction (–)

u(r)

Axial velocity profile in radial direction (–)

(∂u/∂r)w

Wall velocity gradient (s−1)

Greek symbols

α

Thermal diffusivity (m2 s−1)

ρ(T)

Temperature-dependent density (kg m−3)

μ(T)

Temperature-dependent viscosity (N s m−2)

υ

Kinematic viscosity (m2 s−1)

SkT

Thermal conductivity–temperature sensitivity (∂k/∂T)

SμT

Viscosity–temperature sensitivity (∂μ/∂T)

SρT

Density–temperature sensitivity (∂ρ/∂T)

Non-dimensional numbers

Nu

Nusselt number

NuCP

Nusselt number for constant fluid properties

NuVP

Nusselt number for variable fluid properties

Pe

Peclet number

Po

Poiseuille number

Pr

Prandtl number

Re

Reynolds number

Subscripts

D

Based on diameter

ex

Value at outlet

in

Value at inlet

m

Mean value of properties calculated at bulk mean temperature, Tm

w

Condition at wall

Notes

Acknowledgements

The authors would like to thank Dr. Syed Abbas, Assistant Professor, School of Basic Sciences, IIT Mandi, India, for the administrative support.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

References

  1. 1.
    Peng XF, Peterson GP. The effect of thermofluid and geometrical parameters on convection of liquids through rectangular microchannels. Int J Heat Mass Transf. 1995;38:755–8.CrossRefGoogle Scholar
  2. 2.
    Peng XF, Peterson GP. Convective heat transfer and flow friction for water flow in microchannel structures. Int J Heat Mass Transf. 1996;39:2599–608.CrossRefGoogle Scholar
  3. 3.
    Peng XF, Peterson GP, Wang BX. Frictional flow characteristics of water flowing through rectangular microchannels. Exp Heat Transf. 1994;7:249–64.CrossRefGoogle Scholar
  4. 4.
    Peng XF, Peterson GP, Wang BX. Heat transfer characteristics of water flowing through microchannels. Exp Heat Transf. 1994;7:265–83.CrossRefGoogle Scholar
  5. 5.
    Sieder EN, Tate GE. Heat transfer and pressure drop of liquids in tubes. Ind Eng Chem. 1936;28:1429–35.CrossRefGoogle Scholar
  6. 6.
    Kakac S. The effect of temperature-dependent fluid properties on convective heat transfer. In: Kakac S, Shah RK, Aung W, editors. Handbook of single-phase convective heat transfer. New York: Wiley; 1987.Google Scholar
  7. 7.
    Wu HY, Cheng P. Friction factors in smooth trapezoidal silicon microchannels with different aspect ratios. Int J Heat Mass Transf. 2003;46:2519–25.CrossRefGoogle Scholar
  8. 8.
    Wu HY, Cheng P. An experimental study of convective heat transfer in silicon microchannels with different surface conditions. Int J Heat Mass Transf. 2003;46:2547–56.CrossRefGoogle Scholar
  9. 9.
    Li J, Peterson GP, Cheng P. Three-dimensional analysis of heat transfer in a micro-heat sink with single phase flow. Int J Heat Mass Transf. 2004;47:4215–31.CrossRefGoogle Scholar
  10. 10.
    Wang G, Hao L, Cheng P. An experimental and numerical study of forced convection in a microchannel with negligible axial heat conduction. Int J Heat Mass Transf. 2009;52:1070–4.CrossRefGoogle Scholar
  11. 11.
    Herwig H, Hausner O. Critical view on “new results in micro-fluid mechanics”: an example. Int J Heat Mass Transf. 2003;46:935–7.CrossRefGoogle Scholar
  12. 12.
    Adams TM, Abdel-Khalik SI, Jeter SM, Qureshi ZH. An experimental investigation of single-phase forced convection in microchannels. Int J Heat Mass Transf. 1998;41:851–7.CrossRefGoogle Scholar
  13. 13.
    Celata GP, Cumo M, Marconi V, McPhail SJ, Zummo G. Microtube liquid single-phase heat transfer in laminar flow. Int J Heat Mass Transf. 2006;49:3538–46.CrossRefGoogle Scholar
  14. 14.
    Ameel TA, Wang X, Barron RF, Warrington RO. Laminar forced convection in a circular tube with constant heat flux and slip flow. Microscale Thermophys Eng. 1997;1:303–20.CrossRefGoogle Scholar
  15. 15.
    Herwig H. The effect of variable properties on momentum and heat transfer in a tube with constant heat flux across the wall. Int J Heat Mass Transf. 1985;28:423–31.CrossRefGoogle Scholar
  16. 16.
    Herwig H, Voigt M, Bauhaus FJ. The effect of variable properties on momentum and heat transfer in a tube with constant wall temperature. Int J Heat Mass Transf. 1989;32:1907–15.CrossRefGoogle Scholar
  17. 17.
    Yang CY, Chen CW, Lin TY, et al. Heat transfer and friction characteristics of air flow in microtubes. Exp Therm Fluid Sci. 2012;37:12–8.CrossRefGoogle Scholar
  18. 18.
    Yang CY, Lin TY. Heat transfer characteristics of water flow in microtubes. Exp Therm Fluid Sci. 2007;32:432–9.CrossRefGoogle Scholar
  19. 19.
    Nonino C, Del Giudice S, Savino S. Temperature dependent viscosity effects on laminar forced convection in the entrance region of straight ducts. Int J Heat Mass Transf. 2006;49:4469–81.CrossRefGoogle Scholar
  20. 20.
    Nonino C, Del Giudice S, Savino S. Temperature-dependent viscosity and viscous dissipation effects in microchannel flows with uniform wall heat flux. Heat Transf Eng. 2010;31:682–91.CrossRefGoogle Scholar
  21. 21.
    Del Giudice S, Nonino C, Savino S. Effects of viscous dissipation and temperature dependent viscosity in thermally and simultaneously developing laminar flows in microchannels. Int J Heat Fluid Flow. 2007;28:15–27.CrossRefGoogle Scholar
  22. 22.
    Mahulikar SP, Herwig H. Theoretical investigation of scaling effects from macro-to-microscale convection due to variations in incompressible fluid properties. Appl Phys Lett. 2005;86:014105.CrossRefGoogle Scholar
  23. 23.
    Mahulikar SP, Herwig H. Physical effects in laminar microconvection due to variations in incompressible fluid properties. Phys Fluids. 2006;18:073601.CrossRefGoogle Scholar
  24. 24.
    Herwig H, Mahulikar SP. Variable property effects in single-phase incompressible flows through microchannels. Int J Therm Sci. 2006;45:977–81.CrossRefGoogle Scholar
  25. 25.
    Gulhane NP, Mahulikar SP. Variations in gas properties in laminar micro-convection with entrance effect. Int J Heat Mass Transf. 2009;52:1980–90.CrossRefGoogle Scholar
  26. 26.
    Gulhane NP, Mahulikar SP. Numerical study of compressible convective heat transfer with variations in all fluid properties. Int J Therm Sci. 2010;49:786–96.CrossRefGoogle Scholar
  27. 27.
    Gulhane NP, Mahulikar SP. Numerical investigation on laminar microconvective liquid flow with entrance effect and graetz problem due to variation in thermal properties. Heat Transf Eng. 2012;33:748–61.CrossRefGoogle Scholar
  28. 28.
    Gulhane NP, Mahulikar SP. Numerical study of microconvective water-flow characteristics with variations in properties. Nanoscale Microscale Therm. 2011;15:28–47.CrossRefGoogle Scholar
  29. 29.
    Del Giudice S, Savino S, Nonino C. Temperature dependent viscosity and thermal conductivity effects on the laminar forced convection in straight microchannels. J Heat Transf. 2013;135:101003.CrossRefGoogle Scholar
  30. 30.
    Del Giudice S, Savino S, Nonino C. Entrance and temperature dependent property effects in the laminar forced convection in straight ducts with uniform wall temperature. J Phys Conf Ser. 2014;501:012001.CrossRefGoogle Scholar
  31. 31.
    Wang C, Liu S, Wu J, Li Z. Effects of temperature-dependent viscosity on fluid flow and heat transfer in a helical rectangular duct with a finite pitch. Braz J Chem Eng. 2014;31:787–97.CrossRefGoogle Scholar
  32. 32.
    Cheng KX, Chong YS, Ooi KT. Thermal-hydraulic performance of a tapered microchannel. Int Commun Heat Mass Transf. 2018;94:53–60.CrossRefGoogle Scholar
  33. 33.
    Hajmohammadi MR, Alipour P, Parsa H. Microfluidic effects on the heat transfer enhancement and optimal design of microchannels heat sinks. Int J Heat Mass Transf. 2018;126:808–15.CrossRefGoogle Scholar
  34. 34.
    Kumar R, Mahulikar SP. Effect of temperature-dependent viscosity variation on fully developed laminar microconvective flow. Int J Therm Sci. 2015;98:179–91.CrossRefGoogle Scholar
  35. 35.
    Kumar R, Mahulikar SP. Frictional flow characteristics of microconvective flow for variable fluid properties. Fluid Dyn Res. 2015;47:065501.CrossRefGoogle Scholar
  36. 36.
    Kumar R, Mahulikar SP. Physical effects of variable thermophysical fluid properties on flow and thermal development in micro-channel. Heat Transf Eng. 2018;39:374–90.CrossRefGoogle Scholar
  37. 37.
    Kumar R, Mahulikar SP. Physical effects of variable fluid properties on laminar gas microconvective flow. Heat Transf Asian Res. 2017;46:1029–40.CrossRefGoogle Scholar
  38. 38.
    Kumar R, Mahulikar SP. Variable fluid property effect on heat transfer and frictional flow characteristics of water flowing through microchannel. J Eng Thermophys. 2018;27:456–73.CrossRefGoogle Scholar
  39. 39.
    Vishnuprasad S, Haribabu K, Perarasu VT. Experimental study on the convective heat transfer performance and pressure drop of functionalized graphene nanofluids in electronics cooling system. Heat Mass Transf. 2019;55:2221–34.CrossRefGoogle Scholar
  40. 40.
    Topuz A, Engin T, Özalp AA, Erdoğan B, Mert S, Yeter A. Experimental investigation of optimum thermal performance and pressure drop of water-based Al2O3, TiO2 and ZnO nanofluids flowing inside a circular microchannel. J Therm Anal Calorim. 2018;131:2843–63.CrossRefGoogle Scholar
  41. 41.
    Akbari OA, Khodabandeh E, Kahbandeh F, Toghraie D, Khalili M. Numerical investigation of heat transfer of nanofluid flow through a microchannel with heat sinks and sinusoidal cavities by using novel nozzle structure. J Therm Anal Calorim 2019;138:737–52.CrossRefGoogle Scholar
  42. 42.
    Amini Y, Akhavan S, Izadpanah E. A numerical investigation on the heat transfer characteristics of nanofluid flow in a three-dimensional microchannel with harmonic rotating vortex generators. J Therm Anal Calorim 2019.  https://doi.org/10.1007/s10973-019-08402-6.CrossRefGoogle Scholar
  43. 43.
    Darbari B, Rashidi S, Keshmiri A. Nanofluid heat transfer and entropy generation inside a triangular duct equipped with delta winglet vortex generators. J Therm Anal Calorim 2019.  https://doi.org/10.1007/s10973-019-08382-7.CrossRefGoogle Scholar
  44. 44.
    Toghraie D, Abdollah MM, Pourfattah F, Akbari OA, Ruhani B. Numerical investigation of flow and heat transfer characteristics in smooth, sinusoidal and zigzag-shaped microchannel with and without nanofluid. J Therm Anal Calorim. 2018;131:1757–66.CrossRefGoogle Scholar
  45. 45.
    Varzaneh AA, Toghraie D, Karimipour A. Comprehensive simulation of nanofluid flow and heat transfer in straight ribbed microtube using single-phase and two-phase models for choosing the best conditions. J. Therm. Anal. Calorim. 2019; 1–20.Google Scholar
  46. 46.
    Srivastva U, Malhotra RK, Kaushik SC. Review of heat transport properties of solar heat transfer fluids. J Therm Anal Calorim. 2017;130:605–21.CrossRefGoogle Scholar
  47. 47.
    Srivastva U, Malhotra RK, Kaushik SC. Experimental investigation of convective heat transfer properties of synthetic fluid. J Therm Anal Calorim. 2018;132:709–24.CrossRefGoogle Scholar
  48. 48.
    Kumar R, Mahulikar SP. Numerical re-examination of Chilton-Colburn analogy for variable thermophysical fluid properties. J Heat Transf. 2017;139:071701.CrossRefGoogle Scholar
  49. 49.
    Bird RB, Stewart WE, Lightfoot EN. Transport phenomena. New York: Wiley; 2002.Google Scholar
  50. 50.
    McCutcheon SC, Martin JL, Barnwell TO Jr. Water quality. In: Maidment DR, editor. Handbook of hydrology. New York: McGraw-Hill; 1993. p. 11.3–5.Google Scholar
  51. 51.
    Sherman FS. Viscous flow. New York: McGraw-Hill; 1990.Google Scholar
  52. 52.
    Holman JP. Heat transfer. New York: McGraw-Hill; 1990.Google Scholar
  53. 53.
    Shah RK, London AL. Thermal boundary conditions and some solutions for laminar duct flow forced convection. J Heat Transf. 1974;96:159–65.CrossRefGoogle Scholar
  54. 54.
    Prabhu SV, Mahulikar SP. Effects of density and thermal conductivity variations on entropy generation in gas micro-flows. Int J Heat Mass Transf. 2014;79:472–85.CrossRefGoogle Scholar
  55. 55.
    Mahulikar SP, Herwig H, Hausner O, et al. Laminar gas micro-flow convection characteristics due to steep density gradients. EPL. 2004;68:811.CrossRefGoogle Scholar
  56. 56.
    Mahulikar SP, Tso CP. A new classification for thermal development of fluid flow in a circular tube under laminar forced convection. Proc R Soc Lond. 2002;458:669–82.CrossRefGoogle Scholar
  57. 57.
    Mahulikar SP, Herwig H. Physical effects in pure continuum-based laminar micro-convection due to variation of gas properties. J Phys D Appl Phys. 2006;39:4116.CrossRefGoogle Scholar
  58. 58.
    Mahulikar SP, Gulhane NP, Pradhan SD, et al. Pressure drop characteristics in continuum-based laminar compressible microconvective flow. Nanoscale Microscale Therm. 2012;16:181–97.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringDr. B. R. Ambedkar National Institute of TechnologyJalandharIndia
  2. 2.Department of Aerospace EngineeringIndian Institute of Technology BombayMumbaiIndia

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