## THERMAL SCIENCE

International Scientific Journal

### LIMITS FOR THERMAL CONDUCTIVITY OF NANOFLUIDS

**ABSTRACT**

Nanofluids have offered challenges to thermal engineers and attracted many researchers over the past decade to determine the reasons for anomalous enhancement of thermal conductivity in them. Experiments on measurement of nanofluid thermal conductivity have ended in a large degree of randomness and scatter in their values. Hence in this paper, lower and upper limits for thermal conductivity of nanofluids are developed. The upper limit is estimated by coupling heat transfer mechanisms like particle shape, Brownian motion and nanolayer while the lower limit is based on Maxwell's equation. Experimental data from a range of independent published sources is used for validation of the developed limits.

**KEYWORDS**

PAPER SUBMITTED: 2008-09-11

PAPER REVISED: 2009-01-22

PAPER ACCEPTED: 2009-07-11

**THERMAL SCIENCE** YEAR

**2010**, VOLUME

**14**, ISSUE

**1**, PAGES [65 - 71]

- Ahuja, A. S., Augmentation of Heat Transport in Laminar Flow of Polystyrene Suspension: Experiments and Results, Journal of Applied Physics, 46 (1975), 8, pp. 3408-3416
- Masuda, H., et al., N., Alteration of Thermal Conductivity and Viscosity of Liquid by Dispersing Ultra-Fine Particles (Dispersion of g-Al2O3, SiO2 and TiO2 Ultra-Fine Particles), Netsu Bussei (in Japanese), 4 (1993), 4, pp. 227-233
- Choi, S. U. S., Development and Applications of Non-Newtonian Flows, Vol. 66 (Eds. D. A. Singiner, H. P. Wang), ASME, 1995, pp. 99-105
- Eastman, J. A., et al., Enhanced Thermal Conductivity through the Development of Nanofluids, Proceedings, Materials Research Society (MRS), Fall Meeting, Boston, USA, 1997, p. 3
- Lee, S., et al., Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles, Journal of Heat transfer, 121 (1999), pp. 280-289
- Wang, X., Xu, X., Choi, S. U. S., Thermal Conductivity of Nanoparticle-Fluid Mixture, Journal of Thermophysics and Heat Transfer, 13 (1999), 4, pp. 474-480
- Murshed, S. M. S., Leong, K. C., Yang, C., Thermophysical and Electrokinetic Properties of Nanofluids &#8211; A Critical Review, Applied Thermal Engineering, 28 (2008), 17, pp. 2109-2125
- Keblinski, P., et al., Mechanisms of Heat Flow in Suspensions of Nano-Sized Particles (Nanofluids), International Journal of Heat and Mass Transfer, 45 (2002), 4, pp. 855-863
- Jang, S. P., Choi, S. U. S., Role of Brownian Motion in the Enhanced Thermal Conductivity of Nanofluids, Applied Physics Letters, 84 (2004), 24, pp. 4316-4318
- Chandrasekar, M., et al., New Analytical Models to Investigate Thermal Conductivity of Nanofluids, Journal of Nanoscience and Nanotechnology, 9 (2008), pp. 533-538
- Koo, J., Kleinstreuer, C., A New Thermal Conductivity Model for Nanofluids, Journal of Nanoparticle Research, 6 (2004), 6, pp. 577-588
- Xie, H., Fujii, M., Zhang, X., Effect of Interfacial Nanolayer on the Effective Thermal Conductivity of Nanoparticle-Fluid Mixture, International Journal of Heat and Mass Transfer, 48 (2005), 14, pp. 2926-2932
- Yu, W., Choi, S. U. S., The Role of Interfacial Layers in the Enhanced Thermal Conductivity of Nanofluids: a Renovated Maxwell Model, Journal of Nanoparticle Research, 5 (2003), 1, pp. 167-171
- Das, S. K., et al., Temperature Dependence of Thermal Conductivity Enhancement for Nanofluids, Journal of Heat Transfer, 125 (2003), 4, pp. 567-574
- Mintsa, H. A., et al., New Temperature Dependent Thermal Conductivity Data for Water-Based Nanofluids, International Journal of Thermal Sciences, 48 (2009), 2, pp. 363-371
- Maxwell, J. C., A Treatise on Electricity and Magnetism, 2 unabridged 3rd ed., Clarendon Press, Oxford, UK, 1891
- Shukla, R. K., Dhir, V. K., Study of the Effective Thermal Conductivity of Nanofluids, Proceedings, ASME IMECE, Orlando, Fla., USA, 2005, pp. 1-5
- Yu, W., Choi, S. U. S., The Role of Interfacial Layers in the Enhanced Thermal Conductivity of Nanofluids: A Renovated Hamilton-Crosser Model, Journal of Nanoparticle Research, 6 (2004), 4, pp. 355-361
- Avsec, J., Oblak, M., The Calculation of Thermal Conductivity, Viscosity and Thermodynamic Properties for Nanofluids on the Basis of Statistical Nanomechanics, International Journal of Heat and Mass Transfer, 50 (2007), 19, pp. 4331-4341
- Xuan, Y., Li, Q., Heat Transfer Enhancement of Nanofluids, International Journal of Heat and Fluid Flow, 21 (2000), 1, pp. 58-64
- Mansour, R. B., Galanis, N., Nguyen, C. T., Effect of Uncertainties in Physical Properties on Forced Convection Heat Transfer with Nanofluids, Applied Thermal Engineering, 27 (2007), 1, pp. 240-249
- Xie, H. Q., et al., Thermal Conductivity Enhancement of Suspensions Containing Nanosized Alumina Particles, Journal of Applied Physics, 91 (2002), 7, pp. 4568-4572
- Murshed, S. M. S., Leong, K. C., Yang, C., Investigations of Thermal Conductivity and Viscosity of Nanofluids, International Journal of Thermal Sciences, 47 (2008), 5, pp. 560-568
- Zhang, X., Gu, H., Fujii, M., Effective Thermal Conductivity and Thermal Diffusivity of Nanofluids Containing Spherical and Cylindrical Nanoparticles, Experimental Thermal and Fluid Science, 31 (2007), 6, pp. 593-599