Cooling augmentation of subcooled boiling liquid by a nano-particle coated surface

Abstract

A demand for the high performance cooling technology with low operating power exists for the thermal management of the next generation power electronics, such as the IC inverter of electric vehicle. Boiling heat transfer is a promising candidate for the cooling technology because it can remove a large amount of heat from a heat generating device by phase change of the liquid. However, it is well known that Critical Heat Flux (CHF) restricts the maximum cooling performance of boiling heat transfer. Thus, there is a lot of research to increase CHF. In particular, the boiling heat transfer with the heating surface coated with nanofluid is expected to be used for this purpose. There are some reports that the nanofluid layer coated by boiling concentration method in saturated boiling increases CHF. In this study, we demonstrated boiling concentration method for the heating surface using nanofluid at subcooled boiling. Furthermore, microbubble emission boiling (MEB) was also examined by using the obtained heating surface with nanofluid. As a result, it became clear that MEB was observed even if the surface was coated with the nano-particle layer and the nanoparticle layer coated in subcooled boiling can also improve the maximum heat flux.