Heat transfer enhancement by silver nanowire suspensions in microchannel heat sinks

Convection heat transfer and pressure drop characteristics of water based silver nanowire suspensions flowing through CMOS compatible monolithic microchannel heat sinks are investigated experimentally. Three different rectangular channels of 200 μm×50 μm, 100 μm×50 μm and 70 μm×50 μm cross sectional area are used during the experiments. The stability of the silver nanofluids is established by the added polyvinylpyrrolidone (PVP) as the surfactant. To investigate the potential heat transfer enhancement by the silver nanofluids, the experiments are performed with deionized (DI) water, PVP-DI water solution, and the silver nanofluid with added PVP. It is observed that the silver nanofluid had higher heat transfer coefficient than both the PVP-DI water solution, and DI water only. Moreover, all fluids have similar hydrodynamic performance. The prepared silver nanofluid sample is a successful example of a stable nanofluid that has very little surfactant such that the existence of the surfactant does not cause a decrease in the heat transfer coefficient, while maintaining the stability. Upto 56% enhancement in the heat transfer coefficient is reached with practically no increase in the pumping power. The study is the first in using silver nanowire suspensions for heat transfer enhancement.