Applicability of a nanofluid for a thermal hydraulic system : Critical Heat Flux of Al2O3-Water Nanofluid in a Pool Boiling

Abstract

In the present work, a nanofluid with alumina nano-particles suspended in water is adopted as a new coolant instead of conventional water in pool boiling experimental facility with flat heaters. As the experimental results, 23-43% of boiling heat transfer coefficients have been decreased while 13- 33% of critical heat flux values have been increased in the nanofluid compared to pure water. This is related to a change of surface characteristics by the deposition of nano-particles (surface coating). On the other hand, the existence of a liquid film under a massive vapor bubble had been a theoretical premise of a principle mechanism of critical heat flux, significantly difficult to verify through experimental observations. Here, the existence of such a liquid film separating a vapor bubble from a heated solid surface is confirmed using a nanofluid as a dyed water.