Bubble dynamics in pool boiling of nanofluids

Abstract

Bubble dynamics of pool boiling of nanofluids has been experimentally investigated. The boiling surface was prepared with an average surface roughness of 120 nm. Alumina Oxide- water based nanofluids at a constant concentration of 0.05 wt. % have been used in this investigation. The bubble growth rate, bubble departure diameter and departure frequency have been observed using high speed imaging during pool boiling of pure water and nanofluids at a wall superheat of 104.4 ºC. Number of nucleation sites was activated in the case of nanofluid against one site for pure water. The bubble diameter observed in the case of nanofluids was about 60 % smaller than that observed for pure water. Nanofluid’s bubble departure frequency reached 500 Hz while the bubble frequency observed in the case of pure water was about 23 Hz. In addition, the bubble growth rate showed dependence on the type of working fluid used.