Closure relations for the shear stresses in two-fluid models for laminar stratified flow

2004 ◽  
Vol 30 (7-8) ◽  
pp. 877-900 ◽  
Author(s):  
A Ullmann ◽  
A Goldstein ◽  
M Zamir ◽  
N Brauner
Keyword(s):  
Stratified Flow ◽  
Shear Stresses ◽  
Fluid Models ◽  
Closure Relations ◽  
Two Fluid

Wall and Interfacial Shear Stresses in Laminar Two-Phase Stratified Flow in Pipes

2021 ◽  
pp. 103677
Author(s):  
Ayelet Goldstein ◽  
Ofer Eyal ◽  
Amos Ullmann ◽  
Neima Brauner
Keyword(s):  
Stratified Flow ◽  
Interfacial Shear ◽  
Shear Stresses ◽  
Two Phase

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.

Verification of filtered two-fluid models for gas-particle flows in risers

AIChE Journal ◽  
2010 ◽  
Vol 57 (10) ◽  
pp. 2691-2707 ◽  
Author(s):  
Yesim Igci ◽  
Sankaran Sundaresan
Keyword(s):  
Fluid Models ◽  
Particle Flows ◽  
Two Fluid

SECOND ORDER BOUNDARY CONDITIONS FOR THE DRIFT-DIFFUSION EQUATIONS OF SEMICONDUCTORS

1995 ◽  
Vol 05 (04) ◽  
pp. 429-455 ◽  
Author(s):  
A. YAMNAHAKKI
Keyword(s):  
Boundary Conditions ◽  
Test Problem ◽  
Fluid Model ◽  
Diffusion Equations ◽  
Robin Boundary Conditions ◽  
Fluid Models ◽  
Drift Diffusion ◽  
Dirichlet Conditions ◽  
Robin Boundary ◽  
Two Fluid

By an asymptotic analysis of the Boltzmann equation of semiconductors, we prove that Robin boundary conditions for drift-diffusion equations provide a more accurate fluid model than Dirichlet conditions. The Robin conditions involve the concept of the extrapolation length which we compute numerically. We compare the two-fluid models for a test problem. The numerical results show that the current density is correctly computed with Robin conditions. This is not the case with Dirichlet conditions.

Resistance in transition-edge sensors: A comparison of the resistively shunted junction and two-fluid models

2013 ◽  
Vol 87 (2) ◽  
Author(s):  
Douglas A. Bennett ◽  
Daniel S. Swetz ◽  
Daniel R. Schmidt ◽  
Joel N. Ullom
Keyword(s):  
Transition Edge Sensors ◽  
Fluid Models ◽  
Transition Edge ◽  
Two Fluid
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