Cross-Verification of OpenFOAM Code with Embedded Film Condensation Models for VOF Method

Abstract

Surface film condensation processes occur in many technical devices. For designing of industrial condensers, empirical methods are usually used, which, however, are insensitive to some factors affecting the intensity of these processes, which limits the range of their application for design. Using existing methods, it is possible for one to calculate the heat-transfer surface area required to maintain the required heat rate, but it is not possible to specify tube arrangement in the condenser, which determines the flow of the vapor-liquid mixture in the intertube space and, ultimately, the efficiency of the device. To design more efficient condensers, it is necessary to improve the methods, including those based on data obtained using modern methods of numerical modeling of heat and mass transfer processes. One of the promising methods for calculating surface condensation processes in tube bundles is the Volume of Fluid (VOF) method, supplemented by models for taking into account heat and mass transfer at the interphase surface. The VOF method has been implemented in some commercial codes, but the settings of the code parameters and the choice of a suitable mesh and turbulence model for calculating the condensation processes of moving vapor are not at all obvious. Previously, the authors of this work proposed and implemented a modified model of W.H. Lee in the in-house CFD code ANES and the commercial CFD code ANSYS Fluent for calculating heat and mass transfer processes at the interphase surface using the VOF method. The model was verified on typical problems and limited data for tube bundles. In this paper, condensation and turbulent vapor flow models are implemented in the open-source CFD code OpenFOAM. The models were validated on Stefan problems and condensation of moving and stationary vapor of various heat carriers, and cross-verification between OpenFOAM, ANES, and ANSYS Fluent codes was carried out.