Enhanced thermal conductivity of nanofluids: a state-of-the-art review

Abstract

Adding small particles into a fluid in cooling and heating processes is one of the methods to increase the rate of heat transfer by convection between the fluid and the surface. In the past decade, a new class of fluids called nanofluids, in which particles of size 1-100 nm with high thermal conductivity are suspended in a conventional heat transfer base fluid, have been developed. It has been shown that nanofluids containing a small amount of metallic or nonmetallic particles, such as Al 2 O 3 , CuO, Cu, SiO 2 , TiO 2 , have increased thermal conductivity compared with the thermal conductivity of the base fluid. In this work, effective thermal conductivity models of nanofluids are reviewed and comparisons between experimental findings and theoretical predictions are made. The results show that there exist significant discrepancies among the experimental data available and between the experimental findings and the theoretical model predictions.

Particle and thermohydraulic maldistribution of nanofluids in parallel microchannel systems

“…The thermal transport caliber of any nanofluid depends mainly on nanoparticle concentration, thermal conductivity, the diameter of particles, base fluid conductivity and temperature [22]. Several studies [23][24][25] have conclusively reported that nanofluids show great promise for use in cooling technologies. The use of nanofluids in microchannel heat exchangers has been recommended as a potentially feasible solution for cooling microelectronic devices.…”

Air Entrainment During Flame Aerosol Synthesis of Nanoparticles

“…The influence of AE on the evolution and product CuO yield, primary particle, and mobility sizes is investigated. Copper oxide is studied here for its size-dependent applications as active material in Li ion batteries (Waser et al 2013) or thermally conducting nano-fluids (Ozerinc et al 2010), to name a few.…”

Characterization of halloysite-water nanofluid for heat transfer applications

“…This problem can be solved by adding nanoparticles (colloidal particles with main size smaller than 100 nm) into the base fluid. High specific surface of nanoparticles, high dispersion stability, reduced particle clogging and adjustable properties make nanofluids an interesting solution to enhance the performance of heat exchange systems Li et al, 2009;Özerinç et al, 2010;Saidur et al, 2011).…”

“…Heat transfer plays an important role in many fields such as power generation, chemical processes, air conditioning, transportation, microelectronics and any application in which heating and cooling processes are involved. The enhanced efficiency would allow reducing the size of the devices and decrease the operating costs of associated processes Özerinç et al, 2010).…”

“…The second mechanism stimulates phonons transference along large particles or particle aggregates, which involves that particles with large aspect ratio have better heat transfer properties Özerinç et al, 2010). As a result, the size and shape of nanoparticles and clusters formed are the key factors for the thermal conductivity enhancement Prasher et al, 2006;Shima et al, 2010;Warrier et al, 2010;Wu et al, 2010).…”