Numerical study of natural convection boiling in a partially heated Rayleigh-Bénard cell

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.This paper presents a numerical investigation on Rayleigh-Bénard (RB) cell with natural convective liquid boiling, which is vastly different to thermo-fluids nature of its classic single phase counter-part. The study develops a simulation model and examines the unique fluid and thermal characteristics associated with this two-phase RB cell for a range of heater power. The boiling heat transfer curve is obtained covering single phase to boiling process within the RB cell while identifying its unique fluid features. Unlike cellular convective structures in single-phase RB cell, the analysis on this boiling RB cell indicates a fast rising fluid plume emulating “siphoning” fluid action that develops according to heating levels and vapour composition. It also shows that the vapour bubble dynamics critically influence and determine vapour migration within the boiling fluid and heater surface thermal patterns, making this cell behaviour uniquely different to that of traditional RB cell and conventional pool boiling.