Nanofluid

Nanofluid is a fluid containing nanometer-sized particles, called nanoparticles. These fluids are engineered colloidal suspensions of nanoparticles in a base fluid.^[1] The nanoparticles used in nanofluids are typically made of metals, oxides, carbides, or carbon nanotubes. Common base fluids include water , ethylene glycol^[2] and oil.

Nanofluids have novel properties that make them potentially useful in many applications in heat transfer, including microelectronics, fuel cells, pharmaceutical processes, and hybrid-powered engines,^[3]Engine cooling/vehicle thermal management,domestic refrigerator,chiller,heat exchanger,and nuclear reactor.,in grinding,in machining,in Space, defense and ships,and in Boiler flue gas temperature reduction .They exhibit enhanced thermal conductivity and the convective heat transfer coefficient compared to the base fluid.^[4]

In analysis such as computational fluid dynamics (CFD), nanofluids can be assumed to be single phase fluids. Classical theory of single phase fluids can be applied, where physical properties of nanofluid is taken as a function of properties of both constituents and their concentrations.^[5]

nanofluids are supplied by two methods: 1.one-step method 2.two-step method

Smart “Intelligent” Cooling Nanofluids

Realizing the modest thermal conductivity enhancement in conventional nanofluids, a team of researchers at Indira Gandhi Centre for Atomic Research Centre, Kalakkam have developed a new class of magnetically polarizable nanofluids where the thermal conductivity enhancement up to 300% of basefluids is demonstrated. Fatty-acid-capped magnetite nanoparticles of different sizes (3-10 nm) have been synthesized. It has been shown that both the thermal and rheological properties of such magnetic nanofluids are tunable by varying the magnetic field strength and orientation with respect to the direction of heat flow. Further, it has been shown that such response stimuli fluids are reversibly switchable and have applications in miniature devices such as micro- and nano-electromechanical system.^[6] ,^[7] (http://www.nature.com/nnano/reshigh/2008/0208/full/nnano.2008.38.html; http://nanotechweb.org/cws/article/tech/33659

References

1. ^ Buongiorno, J. (March 2006). "Convective Transport in Nanofluids". Journal of Heat Transfer (American Society Of Mechanical Engineers) 128 (3): 240. http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000128000003000240000001&idtype=cvips&gifs=yes&ref=no. Retrieved 27 March 2010. 
2. ^ "Argonne Transportation Technology R&D Center". http://www.transportation.anl.gov/materials/nanofluids.html. Retrieved 27 March 2010. 
3. ^ Das, Sarit K.; Stephen U. S. Choi, Wenhua Yu, and T. Pradeep (2007). Nanofluids: Science and Technology. Wiley-Interscience. pp. 397. http://www3.interscience.wiley.com/cgi-bin/bookhome/114200126?CRETRY=1&SRETRY=0. Retrieved 27 March 2010. 
4. ^ Kakaç, Sadik; Anchasa Pramuanjaroenkij (2009). "Review of convective heat transfer enhancement with nanofluids". International Journal of Heat and Mass Transfer (Elsevier) 52: 3187–3196. doi:10.1016/j.ijheatmasstransfer.2009.02.006. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V3H-4VXNK5N-6&_user=10&_coverDate=06%2F30%2F2009&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1270200460&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=fd79465a35ef5e48fc81c42225b2d50e. Retrieved 27 March 2010. 
5. ^ Maiga, Sidi El Becaye; Palm, S.J.; Nguyen, C.T.; Roy, G; Galanis, N (3). "Heat transfer enhancement by using nanofluids in forced convection flows". International Journal of Heat and Fluid Flow 26: 530–546. 
6. ^ J. Philip, Shima.P.D. & B. Raj (2006). "Nanofluid with tunable thermal properties". Applied Physics Letters 92: 043108. 
7. ^ Shima P.D.and J. Philip (2011). "Tuning of Thermal Conductivity and Rheology of Nanofluids using an External Stimulus". J. Phys. Chem. C xx: x-x. 

European Projects: NanoHex is a European Project developing industrial class nanofluid coolants