Effect of AL2O3 - water nano fluid on bubble spacing in subcooled flow boiling in a horizontal annulus

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In this research work, an experiment has been performed in subcooled flow boiling of Al2O3 – Water nano fluid at different heat fluxes with the intention of investigating the effect of nano particles on bubble spacing in a horizontal, annular test section with an inner heating surface. High speed photography is used to capture bubble images and subsequently processed by National Instruments Labview IMAQ Vision building image processing software. Bubble spacing with respect to variation in heat flux and concentration of nano particles has been evaluated by automated image processing and analysis algorithms. It is observed that bubble spacing decreases with increase in heat flux and concentration of nano particles which is a clear indication of increase in heat transfer coefficients.