Single- and two-fluid models for steam condensing flow modeling

摘要

The paper presents a description of two models dedicated to steam condensing flow modeling. The models are implemented into an in-house computational fluid dynamics (CFD) code that has been successfully applied to a wet steam flow calculation for many years now. Both models use the same condensation model that has been validated against the majority of available experimental data. The state equations for vapor and liquid water, the physical model as well as the numerical techniques of solution to flow governing equations have been presented. For the single-fluid model (SFM), the Reynolds-averaged Navier-Stokes (RANS) equations for vapor/liquid mixture are solved, whereas the two-fluid model solves separate flow governing equations for the compressible, viscous and turbulent vapor phase and for the compressible and inviscid liquid phase.Both described models have been compared with relation to the flow through the Laval nozzle.