Numerical Simulation on Forced Convective Condensation of Steam Upward Flow in a Vertical Pipe

Abstract

A transient three-dimensional volume of fluid (VOF) simulation on condensation of upward flow of wet steam inside a 12 mm i.d. vertical pipe is presented. The effect of gravity and surface tension are taken into account. A uniform wall temperature has been fixed as boundary conditions. The mass flux is 130∼6400 kg m −2 s −1 and the turbulence inside the vapor phase and liquid phase have been handled by Reynolds stress model (RSM). The vapor quality of fluid is 0∼0.4. The numerical simulation results show that, in all the simulation conditions, the bubbly flow, slug flow, churn flow, wispy annular flow, and annular flow are observed; in addition, the results of flow pattern are in good agreement with the regime map from Hewitt and Roberts. The typical velocity field characteristic of each flow pattern and the effect of velocity field on heat transfer of condensation are analyzed, indicating that the slug flow and churn flow have obvious local eddy. However, no obvious eddy is observed in other flow patterns and the streamlines are almost parallel to the flow direction. The simulation results of heat transfer coefficients and frictional pressure drop show good agreement with the correlations from existing literatures.

Modelling of Passive Heat Removal Systems: A Review with Reference to the Framatome KERENA BWR Reactor: Part I

“…Several groups, such as Da Riva et al [77], applied the Lee model (Equation (21)) for simulation of laminar liquid film condensation in a horizontal circular microchannel with the VOF method. Qiu et al [78] conducted a transient VOF simulation of the condensation in an upward flow of wet steam. Liu et al [79] investigated the laminar liquid film generation and its effect on heat transfer with the VOF model.…”

A numerical study on film condensation of steam with non-condensable gas on a vertical plate

“…They observed that the mass concentration and velocity of the non-condensable gas increased from the bulk mixture to the interface. According to the operating conditions, the mass transfer intensity factor is a key empirical coefficient with a wide range in this model (e.g., Alizadehdakhel et al, 2010;Liu et al, 2012;Riva and Col, 2012;Qiu et al, 2014;Lee et al, 2015;Kharangate et al, 2016). More than that, the mass transfer coefficient is usually treated as a constant, which is not physical in the continuous phase change of condensation.…”