Improvement of Interfacial Area Prediction on Condensing Steam-water Flow Using Bubble Collapse Model

Computational Fluid Dynamics (CFD) simulations are performed in this work on an experiment where polydisperse steam bubbles are condensed in sub-cooled water.The saturated steam bubbles are injected in subcooled water inside a large vertical pipe and the steam volume fraction, velocity, bubble size distribution and liquid temperature are measured as radial profile at different heights.Six test cases with various pressure, liquid sub-cooling and diameter of the gas injection orifices are simulated.The simulations are largely improved by the introduction of a bubble collapse model in the Interfacial Area Transport Equation (IATE) of Neptune_CFD code.This model allows to consider the phenomena of polydisperse bubbles condensation despite the monodisperse model used in the one-group IATE and gives equivalent results as MUltiple-SIze Group (MUSIG) model with a reduced computational cost.