Simultaneous mapping of single bubble dynamics and heat transfer rates for SiO2/water nanofluids under nucleate pool boiling regime

Dependence of single vapor bubble dynamics and heat transfer rates on varying concentration of SiO2 nanoparticles for a range of subcooled conditions (0–9 °C) has been experimentally studied under nucleate pool boiling configuration. Non-invasive measurements have been carried out using rainbow schlieren deflectometry. Results on bubble dynamics showed that the bubble diameter and aspect ratio decrease with increasing subcooling levels as well as concentration of nanofluids. The frequency of bubble oscillations was found to increase first and then decrease with increasing subcooling levels while it decreases monotonically with increasing nanofluid concentration. Bubble departure frequency increased significantly for nanofluids, while it decreased with increasing subcooling levels. Condensation effects at the bubble interface were reflected in the form of redistribution of colors around it. Schlieren images clearly revealed a spread in the spatial extent of the thermal boundary layer region caused by the s...