Cooling Performance of Nanofluids in a Microchannel Heat Sink

This paper describes an experimental study on microchannel heat sink performance where ZnO nanoparticle suspended fluids are used as coolant. The microchannel heat sink has 65 parallel microchannels branched out from an inlet reservoir and then collected into an outlet reservoir. Its fabrication process is based on the standard photolithographic microfabrication technology. A main feature of the heat sink has an array of on-chip temperature sensors on the channel bottom surface along the channel. Thus, the channel wall temperatures are directly measured. Heat transfer coefficient for the nanofluid is measured and compared with that of DI water as reference. The experiments show that the heat transfer coefficient of the ZnO nanofluid is 13% higher than that of the base fluid at the Reynolds number of 3.8, although it is comparable with that of DI water at lower Re numbers. The experiments also show that the heat transfer coefficient as well as the Nusselt number increases as the Reynolds number increases.