Silicon carbide nanowires suspensions with high thermal transport properties

Abstract

Nanofluids have a broad prospect for thermal management applications in many fields. In this paper, ethylene glycol (EG) suspensions containing silicon carbide (SiC) nanowires were prepared by mechanical mixing. The average thermal conductivity of suspensions with SiC nanowires is greatly improved compared with that of pure EG, and it increases with the volume fraction of SiC nanowires. When the SiC loading is 5.0 vol.%, the thermal conductivity of the suspension was 0.443W/mK, increasing 67.2% with respect to pure EG. There is no obvious temperature dependency for the thermal conductivity enhancement ratio. These experimental results are in reasonable agreement with predicted values of Hamilton–Crosser model. The research confirms that the shape factor of SiC has a critical effect on the effective thermal conductivity of suspensions. Meanwhile, it validates that the SiC nanowires have stronger ability to enhance thermal conductivity of suspensions than the other shapes. It is due to the large aspect ratio of SiC nanowires, which can easily form bridges between them, known as conductive network. The formation of random bridges or networks from conductive particles facilitates phonon transfer, leading to high thermal conductivity.