Abstract
Over the last decade nanofluids (colloidal suspensions of solid nanoparticles) sparked excitement as well as controversy. In particular, a number of researches reported dramatic increases of thermal conductivity with small nanoparticle loading, while others showed moderate increases consistent with the effective medium theories on well-dispersed conductive spheres. Accordingly, the mechanism of thermal conductivity enhancement is a hotly debated topic. We present a critical analysis of the experimental data in terms of the potential mechanisms and show that, by accounting for linear particle aggregation, the well established effective medium theories for composite materials are capable of explaining the vast majority of the reported data without resorting to novel mechanisms such as Brownian motion induced nanoconvection, liquid layering at the interface, or near-field radiation. However, particle aggregation required to significantly enhance thermal conductivity, also increases fluid viscosity rendering the benefit of nanofluids to flow based cooling applications questionable.
Similar content being viewed by others
References
Ben-Abdallah P (2006) Heat transfer through near-field interactions in nanofluids. Appl Phys Lett 89:113–117
Choi SUS (1995) Enhancing thermal conductivity of fluids with nanoparticles. In: Siginer DA, Wang HP, Div FE (eds) Developments and applications of non-newtonian flows. American Society of Mechanical Engineers, New York, pp 99–105
Choi SUS, Zhang ZG, Yu W, Lockwood FE, Grulke EA (2001) Anomalous thermal conductivity enhancement in nanotube suspensions. Appl Phys Lett 79:2252–2254
Chopkar M, Das PK, Manna I (2006) Synthesis and characterization of nanofluid for advanced heat transfer applications. Scripta Materialia 55:549–552
Chopkar M, Kumar S, Bhandari DR, Das PK, Manna I (2007) Development and characterization of Al2Cu and Ag2Al nanoparticle dispersed water and Ethylene glycol based nanofluid. Mat Sci Eng: B 139:141–148
Das SK, Putra N, Thiesen P, Roetzel W (2003) Temperature dependence of thermal conductivity enhancement for nanofluids. J Heat Transfer 125:567–574
Domingues G, Volz S, Joulain K, Greffet J-J (2005) Heat transfer between two nanoparticles through near field interaction. Phys Rev Lett 94:085901
Eapen J, Li J, Yip S (2007a) Beyond the Maxwell limit: thermal conduction in nanofluids with percolating fluid structures. Phys Rev E 76:062501
Eapen J, Li J, Yip S (2007b) Mechanism of thermal transport in dilute nanocolloids. Phys Rev Lett 98:028302
Eapen J, Buongiorno J, Hu L-W, Yip S, Rusconi R, Piazza R (2007c) Mean-field bounds and the classical nature of thermal conduction in nanofluids. Manuscript under preparation
Eapen J, Williams WC, Buongiorno J, Hu L-W, Yip S, Rusconi R, Piazza R (2007d) Mean-field versus microconvection effects in nanofluid thermal conduction. Phys Rev Lett 99:095901
Eastman JA, Choi SUS, Li S, Thompson LJ, Lee S (1997) Enhanced thermal conductivity through the development of nanofluids, 3–11. Materials Research Society (MRS): Fall Meeting, Boston, USA
Eastman JA, Choi SUS, Li S, Yu W, Thompson LJ (2001) Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles. Appl Phys Lett 78:718–720
Evans W, Fish J, Keblinski P (2006) Role of Brownian motion hydrodynamics on nanofluid thermal conductivity. Appl Phys Lett 88:093116
Every AG, Tzou Y, Hasselmanan DPH, Raj R (1992) The effect of particle size on the thermal conductivity of ZnS/diamond composites. Acta Metallurgica et Materialia 40:123–129
Hashin Z, Shtrikman S (1962) A variational approach to the theory of the effective magnetic permeability of multiphase materials. J Appl Phys 33:3125
Hong KS, Hong T-K, Yang H-S (2006) Thermal conductivity of Fe nanofluids depending on the cluster size of nanoparticles. Appl Phys Lett 88:031901
Hong TK, Yang HS, Choi CJ (2005) Study of the enhanced thermal conductivity of Fe nanofluids. J Appl Phys 97:064311
Huxtable ST, Cahill DG, Shenogin S, Xue L, Ozisik R, Barone P, Usrey M, Strano MS, Siddons G, Shim M, Keblinski P (2003) Interfacial heat flow in carbon nanotube suspension. Nature Materials 2
Hwang Y, Lee JK, Lee CH, Jung YM, Cheong SI, Lee CG, Ku BC, Jang SP (2007) Stability and thermal conductivity characteristics of nanofluids. Thermochimica Acta 455:70–74
Jang SP, Choi SUS (2004) Role of Brownian motion in the enhanced thermal conductivity of nanofluids. Appl Phys Lett 84:4316–4318
Kang HU, Kim SH, Oh JM (2006) Estimation of thermal conductivity of nanofluid using experimental effective particle volume. Exp Heat Trans 19:181–191
Keblinski P, Eastman JA, Cahill DG (2005) Nanofluids for thermal transport. Mat Today 8:36–44
Keblinski P, Phillpot SR, Choi SUS, Eastman JA (2002) Mechanisms of heat flow in suspensions of nano-sized particles (nanofluids). Int J Heat Mass Trans 45:855–863
Kim SH, Choi SR, Kim D (2007) Thermal conductivity of metal-oxide nanofluids: particle size dependence and effect of laser irradiation. J Heat Transfer 129:298–307
Koo J, Kleinstreuer C (2004) A new thermal conductivity model for nanofluids. J Nanopart Res 6:577–588
Kwak K, Kim C (2005) Viscosity and thermal conductivity of copper oxide nanofluid dispersed in ethylene glycol. Korea-Aust Rheol J 17:35–40
Landauer R (1952) The electrical resistance of binary metallic mixtures. J Appl Phys 23:779–784
Lee S, Choi SUS, Li S, Eastman JA (1999) Measuring thermal conductivity of fluids containing oxide nanoparticles. J Heat Transfer 121:280–289
Li CH, Peterson GP (2006) Experimental investigation of temperature and volume fraction variations on the effective thermal conductivity of nanoparticle suspensions (nanofluids). J Appl Phys 99:084314
Masuda H, Ebata A, Teramae K, Hishinuma N (1993) Alteration of thermal conductivity and viscosity of liquid by dispersing ultra-fine particles (Dispersion of γ-Al2O3, SiO2, and TiO2 ultra-fine particles). Netsu Bussei (Japan) 7:227–233
Maxwell JC (1881) A Treatise on electricity and magnetism, II edn. Claredon, Oxford
Murshed SMS, Leong KC, Yang C (2005) Enhanced thermal conductivity of TiO2-water based nanofluids. Int J Therm Sci 44:367–373
Murshed SMS, Leong KC, Yang C (2006) Determination of the effective thermal diffusivity of nanofluids by the double hot-wire technique. J Phys D: Appl Phys 39:5316–5322
Nan C-W, Birringer R, Clarke DR, Gleiter H (1997) Effective thermal conductivity of particulate composites with interfacial thermal resistance. J Appl Phys 81:6692–6699
Patel HE, Das SK, Sundararajan T, Nair AS, George B, Pradeep T (2003) Thermal conductivities of naked and monolayer protected metal nanoparticle based nanofluids: Manifestation of anomalous enhancement and chemical effects. Appl Phys Lett 83:2931–2933
Prasher R, Bhattacharya P, Phelan PE (2005) Thermal conductivity of nanoscale colloidal solutions (nanofluids). Phys Rev Lett 94:025901
Prasher R, Evans W, Meakin P, Fish J, Phelan P, Keblinski P (2006a) Effect of aggregation on thermal conduction in colloidal nanofluids. Appl Phys Lett 89:143119
Prasher R, Phelan PE, Bhattacharya P (2006b) Effect of aggregation kinetics on the thermal conductivity of nanoscale colloidal solutions (nanofluid). Nano Lett 6:1529–1534
Prasher R, Song D, Wang J, Phelan P (2006c) Measurements of nanofluid viscosity and its implications for thermal applications. Appl Phys Lett 89:133108
Putnam SA, Cahill DG, Braun PV, Ge Z, Shimmin RG (2006) Thermal conductivity of nanoparticle suspensions. J Appl Phys 99:084308
Rusconi R, Rodari E, Piazza R (2006) Optical measurements of the thermal properties of nanofluids. Appl Phys Lett 89:261916
Shaikh S, Lafdi K, Ponnappan R (2007) Thermal conductivity improvement in carbon nanoparticle doped PAO oil: an experimental study. J Appl Phys 101:064302
Venerus DC, Kabadi MS, Lee S, Perez-Luna V (2006) Study of thermal transport in nanoparticle suspensions using forced Rayleigh scattering. J Appl Phys 100:094310
Vladkov M, Barrat J-L (2006) Modeling transient absorption and thermal conductivity in a simple nanofluid. Nano Lett 6:1224–1228
Wen D, Ding Y (2004a) Effective thermal conductivity of aqueous suspensions of carbon nanotubes (carbon nanotube nanofluids). J Thermophys Heat Transfer 18:481–485
Wen D, Ding Y (2004b) Experimental investigation into convective heat transfer of nanofluids at the entrance region under laminar flow conditions. Int J Heat Mass Trans 47:5181–5188
Wen D, Ding Y (2006) Natural convective heat transfer of suspensions of titanium dioxide nanoparticles (nanofluids). IEEE Trans Nanotech 5:220–227
Wilson OM, Hu X, Cahill DG, Braun PV (2002) Colloidal metal particles as probes of nanoscale thermal transport in fluids. Phys Rev B 66:224301
Xue L, Keblinski P, Phillpot SR, Choi SUS, Eastman JA (2004) Effect of liquid layering at the liquid–solid interface on thermal transport. Int J Heat Mass Trans 47:4277–4283
Yu C-J, Richter AG, Kmetko J, Dugan SW, Datta A, Dutta P (2001) Structure of interfacial liquids: X-ray scattering studies. Phys Rev E 63:021205
Zhang X, Gu H, Fujii M (2006a) Effective thermal conductivity and thermal diffusivity of nanofluids containing spherical and cylindrical nanoparticles. J Appl Phys 100:044325
Zhang X, Gu H, Fujii M (2006b) Experimental Study on the Effective Thermal Conductivity and Thermal Diffusivity of Nanofluids. Int J Thermophysics 27:569–580
Zhu H, Zhang C, Liu S, Tang Y, Yin Y (2006) Effects of nanoparticle clustering and alignment on thermal conductivities of Fe3O4 aqueous nanofluids. Appl Phys Lett 89:023123
Zhu HT, Zhang CY, Tang YM, Wang JX (2007) Novel synthesis and thermal conductivity of CuO nanofluid. J Phys Chem C 111:1646–1650
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Keblinski, P., Prasher, R. & Eapen, J. Thermal conductance of nanofluids: is the controversy over?. J Nanopart Res 10, 1089–1097 (2008). https://doi.org/10.1007/s11051-007-9352-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11051-007-9352-1