Quantitative comparison between volume-of-fluid and two-fluid models for two-phase flow simulation using OpenFOAM

2020 ◽  
Vol 34 (3) ◽  
pp. 1157-1166
Author(s):  
Thinh Quy Duc Pham ◽  
Jichan Jeon ◽  
Sanghun Choi
Keyword(s):  
Two Phase Flow ◽  
Flow Simulation ◽  
Volume Of Fluid ◽  
Quantitative Comparison ◽  
Phase Flow ◽  
Fluid Models ◽  
Two Phase ◽  
Two Fluid

Modeling of Sodium Two-Phase Flow With the TRACE Code

2009 ◽  
Author(s):  
Aurelia Chenu ◽  
Konstantin Mikityuk ◽  
Rakesh Chawla
Keyword(s):  
Single Phase ◽  
Two Phase Flow ◽  
Flow Simulation ◽  
Phase Flow ◽  
Fluid Models ◽  
Code System ◽  
Two Phase ◽  
Liquid Flows ◽  
Transfer Mechanisms ◽  
Two Fluid

In the framework of PSI’s FAST code system, the TRACE thermal-hydraulics code is being extended for representation of sodium two-phase flow. As the currently available version (v.5) is limited to the simulation of only single-phase sodium flow, its applicability range is not enough to study the behavior of a Sodium-cooled Fast Reactor (SFR) during a transient in which boiling is anticipated. The work reported here concerns the extension of the two-fluid models, which are available in TRACE for steam-water, to sodium two-phase flow simulation. The conventional correlations for ordinary gas-liquid flows are used as basis, with optional correlations specific to liquid metal when necessary. A number of new models for representation of the constitutive equations specific to sodium, with a particular emphasis on the interfacial transfer mechanisms, have been implemented and compared with the original closure models. As a first application, the extended TRACE code has been used to model experiments that simulate a loss-of-flow (LOF) accident in a SFR. The comparison of the computed results, with both the experimental data and SIMMER-III code predictions, has enabled validation of the capability of the modified TRACE code to predict sodium boiling onset, flow regimes, dryout, flow reversal, etc. The performed study is a first-of-a-kind application of the TRACE code to two-phase sodium flow. Other integral experiments are planned to be simulated to further develop and validate the two-phase sodium flow methodology.

Validation of 2D CFD for Two-Phase Transient Flow in a Channel and Comparison With 1D Model

2012 ◽  
Author(s):  
Stamatis Kalogerakos ◽  
Mustapha Gourma ◽  
Chris Thompson
Keyword(s):  
Flow Regime ◽  
Slug Flow ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Volume Of Fluid ◽  
Inviscid Limit ◽  
Phase Flow ◽  
Two Phase ◽  
Vof Model ◽  
Two Fluid

Severe limitations of the use of three-dimensional computational fluid dynamics codes (CFD) arise when trying to simulate multiphase flow in long pipes due to time constraints. 1D codes for two-phase flow, based on two-fluid models, are fast but are known to be accurate only when the velocities are within the Kelvin-Helmholtz inviscid limit [1]. An alternative is to carry out a two-dimensional CFD simulation of a channel based on the Volume of Fluid (VOF) model. 2D CFD has a wider applicability range compared to 1D, it does not have the issue of ill-posedness and it also has better turbulence models built in. Again compared to 1D the 2D VOF model has a better interface description and wall treatment. In this paper a novel method is introduced that allows swift simulations of pipeline two-phase flow in the stratified and slug flow regime, by approximating the pipe as a channel and with a methodology that solves the problem of the interfacial velocity differences, inherent in the volume of fluid model. An initial validation using the wave growth problem has already been carried out [2]. Here a set consisting of 92 experimental cases in the slug flow regime has been simulated with 2D CFD, and the simulation results showed a good agreement with experimental results. Discussions in the paper include also the question of the range of applicability for 2D CFD, and the advantages and disadvantages compared to 3D CFD and also to 1D code based on the two-fluid model. Shear stresses are then extracted from the 2D CFD simulations and used to recalibrate the friction factors [3] used in the 1D code.

First and Second-Order Accurate Schemes for Two-Fluid Models

1998 ◽  
Vol 120 (2) ◽  
pp. 363-368 ◽  
Author(s):  
Iztok Tiselj ◽  
Stojan Petelin
Keyword(s):  
Two Phase Flow ◽  
Second Order ◽  
Minor Role ◽  
Phase Flow ◽  
Fluid Models ◽  
Two Phase ◽  
Large Computer ◽  
Wide Range ◽  
Fast Transients ◽  
Two Fluid

The six-equation two-fluid model of two-phase flow taken from the RELAP5/MOD3 computer code has been used to simulate three simple transients: a two-phase shock tube problem, the Edwards Pipe experiment, and water hammer due to rapid valve closure. These transients can be characterized as fast transients, since their characteristic time-scales are determined by the sonic velocity. First and second-order accurate numerical methods have been applied both based on the well-known, Godunov-type numerical schemes. Regarding the uncertainty of the two-fluid models in today’s large computer codes for the nuclear thermal-hydraulics, use of second-order schemes is not always justified. While this paper shows the obvious advantage of second-order schemes in the area of fast transients, first-order accurate schemes may still be sufficient for a wide range of two-phase flow transients where the convection terms play a minor role compared to the source terms.

Coupling of the Interface Tracking and the Two-Fluid Models for the Simulation of Incompressible Two-Phase Flow

2001 ◽  
Vol 171 (2) ◽  
pp. 776-804 ◽  
Author(s):  
Gregor C̆erne ◽  
Stojan Petelin ◽  
Iztok Tiselj
Keyword(s):  
Two Phase Flow ◽  
Interface Tracking ◽  
Phase Flow ◽  
Fluid Models ◽  
Two Phase ◽  
Two Fluid
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