{"title":"Estimation of Thermal Conductivity of Nanofluids Using MD-Stochastic Simulation Based Approach","authors":"Sujoy Das, M. M. Ghosh","volume":97,"journal":"International Journal of Materials and Metallurgical Engineering","pagesStart":75,"pagesEnd":81,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/10000294","abstract":"
The thermal conductivity of a fluid can be
\r\nsignificantly enhanced by dispersing nano-sized particles in it, and
\r\nthe resultant fluid is termed as "nanofluid". A theoretical model for
\r\nestimating the thermal conductivity of a nanofluid has been proposed
\r\nhere. It is based on the mechanism that evenly dispersed
\r\nnanoparticles within a nanofluid undergo Brownian motion in course
\r\nof which the nanoparticles repeatedly collide with the heat source.
\r\nDuring each collision a rapid heat transfer occurs owing to the solidsolid
\r\ncontact. Molecular dynamics (MD) simulation of the collision
\r\nof nanoparticles with the heat source has shown that there is a pulselike
\r\npick up of heat by the nanoparticles within 20-100 ps, the extent
\r\nof which depends not only on thermal conductivity of the
\r\nnanoparticles, but also on the elastic and other physical properties of
\r\nthe nanoparticle. After the collision the nanoparticles undergo
\r\nBrownian motion in the base fluid and release the excess heat to the
\r\nsurrounding base fluid within 2-10 ms. The Brownian motion and
\r\nassociated temperature variation of the nanoparticles have been
\r\nmodeled by stochastic analysis. Repeated occurrence of these events
\r\nby the suspended nanoparticles significantly contributes to the
\r\ncharacteristic thermal conductivity of the nanofluids, which has been
\r\nestimated by the present model for a ethylene glycol based nanofluid
\r\ncontaining Cu-nanoparticles of size ranging from 8 to 20 nm, with
\r\nGaussian size distribution. The prediction of the present model has
\r\nshown a reasonable agreement with the experimental data available
\r\nin literature.<\/p>\r\n","references":"[1] Eastman J. A., Choi S. U. S., Li S., Yu W., and Thompson L. J.,\r\n\"Anomalously increased effective thermal conductivities of ethylene\r\nglycol-based nanofluids containing copper nanoparticles\", Applied\r\nPhysics Letters, 78, pp. 718-720, 2001.\r\n[2] Choi S. U. S., Zhang Z. G., Yu W., Lockwood F. E., and Grulke E. A.,\r\n\"Anomalous thermal conductivity enhancement in nanotube\r\nsuspensions\", Applied Physics Letters, 79, pp. 2252-2254, 2001.\r\n[3] Das S. K., Putra N., Thiesen P., and Roetzel W., \"Temperature\r\nDependence of Thermal Conductivity Enhancement for Nanofluids\",\r\nJournal of Heat Transfer, 125, pp. 567-574, 2003.\r\n[4] Patel H. E., Das S. K., Sundararajan T., Nair A. S., George B., and\r\nPradeep T., \"Thermal conductivities of naked and monolayer protected\r\nmetal nanoparticle based nanofluids: Manifestation of anomalous\r\nenhancement and chemical effects\", Applied Physics Letters, 83, pp.\r\n2931-2933, 2003.\r\n[5] Lee S., Choi S. U. S., Li S., and Eastman J. A., \"Measuring Thermal\r\nConductivity of Fluids Containing Oxide Nanoparticles\", Journal of\r\nHeat Transfer, 121, pp. 280-289, 1999.\r\n[6] Shukla R. K. and Dhir V. K., \"Study of the effective thermal\r\nconductivity of nanofluids\", in: Proceedings of the ASME International\r\nMechanical Engineering Congress and Exposition (Orlando, Florida,\r\nUSA), November 5-11, 2005, pp. 1-5.\r\n[7] Bhattacharya P., Saha S. K., Yadav A., Phelan P. E., and Prasher R. S.,\r\n\"Brownian dynamics simulation to determine the effective thermal\r\nconductivity of nanofluids\", Journal of Applied Physics, 95, pp. 6492-\r\n6494, 2004.\r\n[8] Jang S. P. and Choi S. U. S., \"Role of Brownian motion in the enhanced\r\nthermal conductivity of nanofluids\", Applied Physics Letters, 84, pp.\r\n4316-4318, 2004.\r\n[9] Prasher R., Bhattacharya P., and Phelan P. E., \"Brownian-Motion-Based\r\nConvective-Conductive Model for the Effective Thermal Conductivity\r\nof Nanofluids\", Journal of Heat Transfer, 128, pp. 588-595, 2006.\r\n[10] Leong K. C., Yang C., and Murshed S. M. S., \"A model for the thermal\r\nconductivity of nanofluids-the effect of interfacial layer\", Journal of\r\nNanoparticle Research, 8, pp. 245-254, 2006.\r\n[11] Prasher R., Evans W., Meakin P., Fish J., Phelan P., and Keblinski P.,\r\n\"Effect of aggregation on thermal conduction in colloidal nanofluids\",\r\nApplied Physics Letters, 89, p. 143119, 2006.\r\n[12] Maxwell J. C., A Treatise on Electricity and Magnetism, 2nd ed., Oxford\r\nUniversity Press, Cambridge, 1904, pp. 435-441.\r\n[13] Hamilton R. L. and Crosser O. K., \"Thermal Conductivity of\r\nHeterogeneous Two-Component Systems\", I & EC Fundamentals, 1, pp.\r\n187-191, 1962.\r\n[14] Bonny G., Pasianot R. C., Malerba L., and Castin N., \"Ternary Fe-Cu-Ni\r\nmany-body potential to model reactor pressure vessel steels: First\r\nvalidation by simulated thermal annealing\", Phylosophical Magazine,\r\n89, pp. 3531-3546, 2009.\r\n[15] Nelson E., Dynamical Theories of Brownian Motion, 2nd ed., (Princeton\r\nUniversity Press, New Jersey, USA, 2001), Ch. 9, pp. 45-52. [16] John W., Reischl G., and Devor W., \"Charge transfer to metal surfaces\r\nfrom bouncing aerosol particles\", Journal of Aerosol Science, 11, pp.\r\n115-138, 1980.\r\n[17] Bandyopadhyay K., Ghosh K. S., and Ghosh M. M., \"Molecular\r\ndynamics based approach for the estimation of tensile properties of\r\nnanoparticles\" (unpublished).\r\n[18] Garg J., Poudel B., Chiesa M., Gordon J. B., Ma J. J., Wang J. B., Ren\r\nZ. F., Kang Y. T., Ohtani H., Nanda J., McKinley G. H., and Chen G.,\r\n\"Enhanced thermal conductivity and viscosity of copper nanoparticles in\r\nethylene glycol nanofluid\", Journal of Applied Physics, 103, p. 074301,\r\n2008.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 97, 2015"}