Two-fluid modelling of the rewetting and refilling of hot horizontal tubes

Abstract

This paper deals with the use of a two‐fluid model for predicting the thermal‐hydraulic characteristics of the rewetting and refilling of hot horizontal tubes. The two‐fluid model equations were simplified and solved using an explicit finite difference scheme. A set of constitutive equations is used for closure. A new film boiling model and a model for evaluating the rate of latent to total heat in film boiling were incorporated in the two‐fluid model. A newly proposed rewetting criterion, based on vapour film collapse, was used to mark the end of the film boiling regime. The model is capable of predicting the rewetting and refilling process in horizontal tubes under conditions of stratified or inverted annular refilling flow. The model predictions were found to be in good agreement with the experimental results.