Enhancing Numerical Stability of a Two-Fluid Model by the Use of Interfacial Pressure Terms

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
Tomio Okawa
Keyword(s):  
Numerical Stability ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Subcooled Flow Boiling ◽  
Interfacial Pressure ◽  
Two Fluid Model ◽  
Two Fluid

Analytical and numerical investigations were carried out to show that the characteristics and the numerical stability of the two-fluid model are improved by the use of the interfacial pressure terms that express the pressure difference between bubbles and continuous liquid phase in bubbly two-phase flow. In particular, it was demonstrated that the numerical stability is enhanced not only in the simulation of adiabatic two-phase flow but also in the simulation of subcooled flow boiling.

Effect of Interfacial Pressure Term on Numerical Stability of a Two-Fluid Model

2014 ◽  
Author(s):  
Tomio Okawa ◽  
Yoshiro Kudo
Keyword(s):  
Numerical Stability ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Fluid Model ◽  
Phase Flow ◽  
Numerical Instability ◽  
Two Phase ◽  
Interfacial Pressure ◽  
Two Fluid Model ◽  
Two Fluid

Mathematical ill-posedness of the governing equations is one the main causes of numerical instability encountered in numerical simulation of two-phase flow using a two-fluid model. It is known that the ill-posedness can be mitigated if the difference between the average pressures of gas and liquid phases is taken into consideration appropriately. In the present work, it was investigated how the numerical stability of the one-dimensional, two-fluid model is influenced by the interfacial pressure terms that express the pressure difference between bubbles and continuous liquid phase in bubbly two-phase flow. Analyses were carried out for adiabatic air-water two-phase flow and subcooled flow boiling. It was confirmed that the interfacial pressure terms are effective to mitigate the numerical instability induced by the mathematical ill-posedness of the two-fluid model. However, the standard interfacial pressure terms deteriorated the numerical stability in some cases. It was found that the simplified model in which the spatial gradients of relative velocity and fluid density are eliminated is effective for the mitigation of numerical instability in wider analytical conditions.

scholarly journals Natural modes of the two-fluid model of two-phase flow

2021 ◽  
Vol 33 (3) ◽  
pp. 033324
Author(s):  
Alejandro Clausse ◽  
Martín López de Bertodano
Keyword(s):  
Two Phase Flow ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Natural Modes ◽  
Two Fluid Model ◽  
Two Fluid

A Physically Based, One-Dimensional Two-Fluid Model for Direct Contact Condensation of Steam Jets Submerged in Subcooled Water

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
David Heinze ◽  
Thomas Schulenberg ◽  
Lars Behnke
Keyword(s):  
Direct Contact ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Contact Condensation ◽  
Two Fluid

A simulation model for the direct contact condensation of steam in subcooled water is presented that allows determination of major parameters of the process, such as the jet penetration length. Entrainment of water by the steam jet is modeled based on the Kelvin–Helmholtz and Rayleigh–Taylor instability theories. Primary atomization due to acceleration of interfacial waves and secondary atomization due to aerodynamic forces account for the initial size of entrained droplets. The resulting steam-water two-phase flow is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations, which is solved by means of the explicit Runge–Kutta–Fehlberg algorithm. The simulation results are in good qualitative agreement with published experimental data over a wide range of pool temperatures and mass flow rates.

A NUMERICAL STUDY OF TWO-PHASE FLOW USING A TWO-DIMENSIONAL TWO-FLUID MODEL

2004 ◽  
Vol 45 (10) ◽  
pp. 1049-1066 ◽  
Author(s):  
Moon-Sun Chung ◽  
Seung-Kyung Pak ◽  
Keun-Shik Chang
Keyword(s):  
Two Phase Flow ◽  
Numerical Study ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Dimensional ◽  
Two Phase ◽  
Two Fluid Model ◽  
Two Fluid

Development of a Transient Mechanistic Two-Phase Flow Model for Wellbores

SPE Journal ◽  
2012 ◽  
Vol 17 (03) ◽  
pp. 942-955 ◽  
Author(s):  
Mahdy Shirdel ◽  
Kamy Sepehrnoori
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Flow Regimes ◽  
Phase Flow ◽  
Two Phase ◽  
Wall Shear ◽  
Two Fluid Model ◽  
Two Fluid

Summary A great deal of research has been focused on transient two-phase flow in wellbores. However, there is lack of a comprehensive two-fluid model in the literature. In this paper, we present an implementation of a pseudo-compositional, thermal, fully implicit, transient two-fluid model for two-phase flow in wellbores. In this model, we solve gas/liquid mass balance, gas/liquid momentum balance, and two-phase energy balance equations to obtain five primary variables: liquid velocity, gas velocity, pressure, holdup, and temperature. This simulator can be used as a stand-alone code or can be used in conjunction with a reservoir simulator to mimic wellbore/reservoir dynamic interactions. In our model, we consider stratified, bubbly, intermittent, and annular flow regimes using appropriate closure relations for interphase and wall-shear stress terms in the momentum equations. In our simulation, we found that the interphase and wall-shear stress terms for different flow regimes can significantly affect the model's results. In addition, the interphase momentum transfer terms mainly influence the holdup value. The outcome of this research leads to a more accurate simulation of multiphase flow in the wellbore and pipes, which can be applied to the surface facility design, well-performance optimization, and wellbore damage estimation.

scholarly journals Prediction of Gas-Liquid Two-Phase Flow Performance of a Centrifugal Pump Using a One-Dimensional, Two-Fluid Model

1997 ◽  
Vol 63 (611) ◽  
pp. 2377-2385
Author(s):  
Kiyoshi MINEMURA ◽  
Tomomi UCHIYAMA ◽  
Katsuhiko KINOSHITA ◽  
Lin LYU ◽  
Shinji SYODA ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Two Fluid
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