Nucleate pool boiling performance of water/titania nanofluid: Experiments and prediction modeling

Abstract

An experimental study to investigate the thermal performance of water/titania (TiO2) nanofluid under nucleate pool boiling was performed. A highly stable water/TiO2 nanofluid with varying weight concentrations of 0.15–1.5% was prepared with the application of polyvinyl alcohol as a surfactant. A dynamic light scattering and zeta potential analyses were performed to confirm the stability of the nanofluids. The effects of varying heat flux and weight concentration on the boiling characteristics and nucleate pool boiling heat transfer coefficient (hNPB) were studied. According to the findings, the hNPB increased as heat flow and weight concentration increased. However, at a higher weight concentration of 1.5%, the enhancement was reduced. The highest enhancement in hNPB of nanofluids was found to be 78.76% with 0.50% weight concentration as compared to water. At the highest wall superheat of ∼16 K, the enhancement almost reduced 71.10% with 1.5% weight concentration. The drop in hNPB was ascribed to the deposition of TiO2 nanoparticles on the heated surface during the boiling process, which resulted in a reduction in nucleation site density. New correlations of high prediction accuracies (R2 > 99.90%) are proposed to relate the wall superheat temperature with heat flux and hNPB.