Role of nanofluids in microchannel heat sinks

Nanofluid is a suspension of solid nanoparticles in base fluid which behaves like a liquid. Nanofluids possess attractive thermal properties making them beneficial for diverse areas in the field of heat transfer such as microelectronics, engine cooling, heat exchangers, machining, etc. Recently, nanofluids have shown increasingly promising interest as a heat transfer medium for application in microchannel heat sinks (MCHS). These heat sinks are typically used in microchips where high heat dissipation is necessary for the integrated circuits for optimum performance. The use of nanotechnology has led to improved thermal conductivity of nanofluids, which has attracted many researchers for its potential application as an advanced cooling fluid in MCHS. The improved thermal characteristics are observed even at low volume fraction of nanoparticles and are dependent on many thermophysical properties of nanoparticles and the base fluid used. Hence, this chapter covers the key characteristics of nanofluids, including their thermophysical properties and the appropriate mathematical models for evaluation of these properties. The flow properties entail the pressure drop and the associated friction factor correlations for nanofluids in MCHS subject to various flow conditions. Lastly, the thermal performance of nanofluids in microchannels is discussed with mathematical correlations for Nusselt number in conjunction with different microchannel geometries.