Heat and Mass Transfer

, Volume 54, Issue 8, pp 2295–2303 | Cite as

Enhancement of natural convection heat transfer in a square cavity using MWCNT/Water nanofluid: an experimental study

  • Pranit Satish Joshi
  • Arvind PattamattaEmail author


In recent times, convective heat transfer using nanofluids has been an active field of research. However experimental studies pertaining to buoyancy induced convective heat transfer using various nanofluid is relatively scarce. In the present study, a square enclosure of dimensions (40 × 40 × 200) mm is used as test section. Initially, Al2O3/Water nanofluid with volume percentage of 0.1%, 0.3%, 1% and 2% and Rayleigh numbers ranging from 7 × 105 to 1 × 107 are studied. These results are then compared with Ho et al. (Int J Therm Sci 49(8):1345–1353, 2010) experimental data. Nusselt number (Nu) is calculated based on the thermophysical properties that are measured in-house for the given conditions. Further, MWCNT/Water nanofluid with volume percentage 0.1%, 0.3% and 0.5% is formulated and are studied for various Rayleigh numbers. Comparison of Al2O3/Water and MWCNT/Water nanofluid have been made for different volume fractions and for various range of Rayleigh numbers. It is observed that MWCNT/Water nanofluid when compared with Al2O3/Water nanofluid yields higher values of the Nusselt number for a given volume fractions. All the existing experimental studies using particle based nanofluid concluded a deterioration in natural convective heat transfer. This study for the first time demonstrates an enhancement in natural convection using MWCNT/Water nanofluid. Such enhancement cannot be simply explained based only on the relative changes in the thermophysical properties. Factors such as percolation network in MWCNT/Water nanofluid which increases the heat transfer pathway between two walls and the role of slip mechanisms might be the possible reasons for the enhancement.



Area of cross section of heater, m 2


Specific heat, J/k g K

\(\overline h\)

Average convective heat transfer coefficient, W/m 2 K


Current, A


Thermal conductivity, W/m K


Nusselt number

\(\overline {Nu}\)

Average Nusselt number


Normalized Nusselt number (N u n o r m = N u n f /N u b f )

\(\overline {q^{\prime \prime }}\)

Average heat flux, W/m 2


Rayleigh number


Temperature, K


Voltage, V


Characteristic length of test cell, m

Greek letters


Coefficient of thermal expansion, 1/K


Uncertainty in the measurement


Dynamic viscosity, P a.s


Volume fraction of nanoparticles


Density, k g/m 3







Correction in heat loss




Heat loss








Total Heat loss



The Authors’ gratefully acknowledge Prof. Amitava Ghosh, Prof. S.K.Das and their students at the Mechanical engineering department, IIT Madras, Prof. Ramaprabhu and his students at the Department of Physics, IIT Madras and Prof. Abhijeet Deshpande and his students at the Department of Chemical engineering, IIT Madras, for allowing them to use the required facilities.


  1. 1.
    Ho C, Liu W, Chang Y, Lin C (2010) Natural convection heat transfer of alumina-water nanofluid in vertical square enclosures: an experimental study. Int J Therm Sci 49(8):1345–1353CrossRefGoogle Scholar
  2. 2.
    Choi S. (1995) Enhancing thermal conductivity of fluids with nanoparticles. ASME-Publications-Fed 231:99–106Google Scholar
  3. 3.
    Putra N, Roetzel W, Das SK (2003) Natural convection of nano-fluids. Heat Mass Transf 39(8–9):775–784CrossRefzbMATHGoogle Scholar
  4. 4.
    Wen D, Ding Y (2005) Formulation of nanofluids for natural convective heat transfer applications. Int J Heat Fluid Flow 26(6):855–864CrossRefGoogle Scholar
  5. 5.
    Nnanna A (2007) Experimental model of temperature-driven nanofluid. J Heat Transf 129(6):697–704CrossRefGoogle Scholar
  6. 6.
    Hu Y, He Y, Wang S, Wang Q, Schlaberg HI (2014) Experimental and numerical investigation on natural convection heat transfer of tio2–water nanofluids in a square enclosure. J Heat Transf 136(2):022502CrossRefGoogle Scholar
  7. 7.
    Paul TC, Morshed A, McCants DA, Khan JA (2013) Buoyancy driven heat transfer behavior of zinc oxide (zno)–water nanofluids. In: ASME 2013 heat transfer summer conference collocated with the ASME 2013 7th international conference on energy sustainability and the ASME 2013 11th international conference on fuel cell science, engineering and technology. American Society of Mechanical Engineers, pp V001T03A008–V001T03A008Google Scholar
  8. 8.
    Kim P, Shi L, Majumdar A, McEuen P (2001) Thermal transport measurements of individual multiwalled nanotubes. Phys Rev Lett 87(21):215502CrossRefGoogle Scholar
  9. 9.
    Choi S, Zhang Z, Yu W, Lockwood F, Grulke E (2001) Anomalous thermal conductivity enhancement in nanotube suspensions. Appl Phys Lett 79(14):2252–2254CrossRefGoogle Scholar
  10. 10.
    Sastry NV, Bhunia A, Sundararajan T, Das SK (2008) Predicting the effective thermal conductivity of carbon nanotube based nanofluids. Nanotechnology 19(5):055704CrossRefGoogle Scholar
  11. 11.
    Gupta SS, Siva VM, Krishnan S, Sreeprasad T, Singh PK, Pradeep T, Das SK (2011) Thermal conductivity enhancement of nanofluids containing graphene nanosheets. J Appl Phys 110(8):084302CrossRefGoogle Scholar
  12. 12.
    Phuoc TX, Massoudi M, Chen R-H (2011) Viscosity and thermal conductivity of nanofluids containing multi-walled carbon nanotubes stabilized by chitosan. Int J Therm Sci 50(1): 12–18CrossRefGoogle Scholar
  13. 13.
    Dhar P, Ansari MHD, Gupta SS, Siva VM, Pradeep T, Pattamatta A, Das SK (2013) Percolation network dynamicity and sheet dynamics governed viscous behavior of polydispersed graphene nanosheet suspensions. J Nanopart Res 15(12):1–12CrossRefGoogle Scholar
  14. 14.
    Maiga SEB, Nguyen CT, Galanis N, Roy G (2004) Heat transfer behaviours of nanofluids in a uniformly heated tube. Superlattices Microstruct 35(3):543–557CrossRefGoogle Scholar
  15. 15.
    Zahari F, Salim MN, Mohamad I, Abdullah N, Thiru S (2015) Thermal properties and heat transfer study of dispersed fluid with functionalized multi-walled carbon nanotube (mwcnt) particles. In: Proceedings of mechanical engineering research day 2015: MERD’15, 2015, pp 11–12Google Scholar
  16. 16.
    Deng L, Young RJ, Kinloch IA, Sun R, Zhang G, Noé L, Monthioux M (2014) Coefficient of thermal expansion of carbon nanotubes measured by raman spectroscopy. Appl Phys Lett 104(5):051907CrossRefGoogle Scholar
  17. 17.
    Savithiri S, Dhar P, Pattamatta A, Das SK (2016) Particle–fluid interactivity reduces buoyancy-driven thermal transport in nanosuspensions: a multi-component lattice boltzmann approach. Numer Heat Transfer, Part A: Appl 70(3):260– 281CrossRefGoogle Scholar
  18. 18.
    Savithiri S, Pattamatta A, Das SK (2011) Scaling analysis for the investigation of slip mechanisms in nanofluids. Nanoscale Res Lett 6(1):1–15CrossRefGoogle Scholar
  19. 19.
    Dhar P, Gupta SS, Chakraborty S, Pattamatta A, Das SK (2013) The role of percolation and sheet dynamics during heat conduction in poly-dispersed graphene nanofluids. Appl Phys Lett 102(16):163114CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Heat Transfer and Thermal Power Laboratory, Department of Mechanical EngineeringIndian Institute of Technology MadrasChennaiIndia

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