Critical Heat Flux Enhancement in Low Flow Boiling of A1_2O_3 Nanofluids under Atmospheric Pressure

摘要

The critical heat flux (CHF) is characterized by a sudden reduction of the local heat transfer coefficient (HTC) that results from the replacement of liquid by vapor adjacent to the heat transfer surface [1]. Many methods to enhance the CHF have been investigated and a new technique in recent years among these methods is nanofluids technology. Nanofluids are nanotechnology-based fluids engineered for enhancing thermal conductivity by dispersing and stably suspending nanoparticles in traditional heat transfer fluids [2]. One of the most interesting characteristics of nanofluids is their capability to enhance the CHF significantly. Kim et al. performed flow boiling CHF experiments using an A1_2O_3 nanofluid at inlet temperature (50, 75 °C) and mass flux (100, 200, 300 kg/m2s). The CHFs of A1_2O_3 nanofluid were enhanced up to 70 % in flow boiling for all experimental conditions [3]. Our experiment was performed at inlet temperature of 25 °C and mass flux (200, 300, 500 kg/m2s).