Nanofluids are a mixture of a small concentration of nanometer-sized solid particles (≤100 nm ) dispersed in a liquid (i.e. water, ethylene glycol, lubricant). In various reports, nanofluids exhibit an anomalous heat transfer performance when compared to its host fluids. In the last two decades, an extensive number of investigations on the heat transfer of nanofluids have been reported. In those reports, nanofluids have been widely regarded as the future coolant in diverse heat transfer applications, one of them is the cooling of microelectronic systems. The microelectronic systems i.e. computer microprocessors are getting smaller and smaller in size, consequently the amount of heat that needs to be dissipated from the system is getting larger and larger. The currently available heat removal systems utilize conduction through metal heat sinks or convection by forcing air to release the heat from the system. These classical methods have reached their limit, heat sink requires a larger dimension to dissipate more heat, on the other hand, air possesses a lower heat transfer ability when compared to water. Another possible solution for the microprocessor cooling system is the microchannel-based liquid cooling, as reported. Microchannel liquid cooling has the ability to remove the heat up to the region of hundreds of W/cm². Microchannels are renowned due to their small size and provide a high surface to volume ratio, thus a higher heat transfer rate was made possible. To date, there is an absence for a definite mechanism on how nanoparticles enhance the heat transfer. Discrepancy in convective heat transfer coefficient is also often found from one to another investigations. In some cases, the available empirical correlation underestimated the convective heat transfer of nanofluids. To address this issue, a reliable measurement setup is required, thus allowing the measurement to provide an accurate and dependable convective heat transfer of nanofluids. The measurement setup was designed and constructed. The test section was made of a copper block, the square microchannel was milled out on the bottom side of the copper block. The microchannel has a cross section of 0.5x0.5 mm² and a length of 30 mm. To ensure the reliability of the setup, the uncertainty of the measurement was checked by using the error propagation method. In the study of transport phenomena, the heat transfer is analogous to the momentum transfer. Studying the momentum transfer of nanofluids through a local velocity measurement could provide a new insight on how nanofluids enhance the heat transfer. The non-intrusive local velocity measurement was performed by using the Astigmatism Particle Tracking Velocimetry (APTV) technique, this method allows the measurement of the flow in three dimensions and provides the information to the flow behavior of nanofluids.    «

Nanofluids are a mixture of a small concentration of nanometer-sized solid particles (≤100 nm ) dispersed in a liquid (i.e. water, ethylene glycol, lubricant). In various reports, nanofluids exhibit an anomalous heat transfer performance when compared to its host fluids. In the last two decades, an extensive number of investigations on the heat transfer of nanofluids have been reported. In those reports, nanofluids have been widely regarded as the future coolant in diverse heat transfer applicat...    »