Heat transfer coefficient and critical heat flux during nucleate pool boiling of water in the presence of nanoparticles of alumina, maghemite and CNTs

The characteristics of nucleate pool boiling were investigated with nanofluids in a chamber. Nanoparticles of alumina, maghemite and carbon nanotubes were added separately to distilled water. Particle volumetric concentrations of 0.02% and 0.10% were applied. Experiments with water on the heater copper surface covered with nanoparticles were conducted to evaluate the effect of deposition. Boiling curves, critical heat fluxes and heat transfer coefficients were obtained and compared to reference data for water. The wettability was determined from contact angle measurements. In the experiments with the nanofluids, the nanoparticles were deposited on the test surface. The static contact angle for the water on the copper oxide surface decreased from around 85 to 0 following the deposition of the nanoparticles. Values for the critical heat flux increased from around 26-37% for all test cases. These results are attributed to the complete wetting behavior presented by the nanoparticles deposited on the test surface. Estimates obtained using the Kandlikar (2001) correlation deviated from the experimental values by less than 9%. The heat transfer coefficients were the same or lower in comparison with the reference case. (C) 2016 Elsevier Ltd. All rights reserved.