Delay in DNB for flow boiling of diluted oxide based nanofluids

Abstract

Flow boiling of Al2O3-water and TiO2-water nanofluids have been investigated with different particle concentrations in a vertical annulus equipped with a concentric cartridge heater at heat fluxes from 30 to 250 kW/m2 and 1 bar pressure to determine bubble behavior by high speed visualization and to study the parametric effect of particle volume fraction and heat flux on bubble dynamics. The important observations include; delayed DNB in case of nano fluids as compared to de-ionized water. Different flow patterns during flow boiling of variable concentration of nanofluids in a vertical annulus were obtained and visualized in terms of bubbly, dispersed bubbly, plug and churn flow. © 2017