scholarly journals Two-phase flow analogy as an effective boundary condition for modelling liquids at atomistic resolution

2016 ◽  
Vol 17 ◽  
pp. 446-456 ◽  
Author(s):  
Ivan Korotkin ◽  
Dmitry Nerukh ◽  
Elvira Tarasova ◽  
Vladimir Farafonov ◽  
Sergey Karabasov
Keyword(s):  
Boundary Condition ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Effective Boundary ◽  
Effective Boundary Condition

Two-phase displacement in Hele Shaw cells: theory

1984 ◽  
Vol 139 ◽  
pp. 291-308 ◽  
Author(s):  
C.-W. Park ◽  
G. M. Homsy
Keyword(s):  
Boundary Condition ◽  
Asymptotic Expansion ◽  
Asymptotic Expansions ◽  
Characteristic Length ◽  
Two Phase ◽  
Phase Displacement ◽  
Effective Boundary ◽  
Small Parameters ◽  
Effective Boundary Condition ◽  
Gap Width

A theory describing two-phase displacement in the gap between closely spaced planes is developed. The main assumptions of the theory are that the displaced fluid wets the walls, and that the capillary number Ca and the ratio of gap width to transverse characteristic length ε are both small. Relatively mild restrictions apply to the ratio M of viscosities of displacing to displaced fluids; in particular the theory holds for M = o(Ca−1/3). We formulate the theory as a double asymptotic expansion in the small parameters ε and Ca1/3. The expansion in ε is uniform while that in Ca1/3 is not, necessitating the use of matched asymptotic expansions. The previous work of Bretherton (1961) is clarified and extended, and both the form and the constants in the effective boundary condition of Chouke, van Meurs & van der Poel (1959) and of Saffman & Taylor (1958) are determined.

Validation Study for VOF Simulations of Boiling in a Microchannel

2015 ◽  
Author(s):  
Catherine Gorlé ◽  
Hyoungsoon Lee ◽  
Farzad Houshmand ◽  
Mehdi Asheghi ◽  
Kenneth Goodson ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Two Phase Flow ◽  
Fluid Simulation ◽  
Experimental Result ◽  
Base Temperature ◽  
Phase Flow ◽  
Two Phase ◽  
Fixed Temperature ◽  
Initial Development ◽  
Flux Boundary Condition

This paper presents a comparison of Volume-of-Fluid simulation results with experiments [1] for two-phase flow and heat transfer in a micro channel. Mass transfer between the phases is modeled using a reduced-order model, requiring the definition of a time relaxation constant, r. A two-step solution procedure is used, where first a fixed temperature boundary condition is imposed at the heater to avoid overheating of the device during the initial development of the two-phase flow. After obtaining a quasi-steady-state solution this is changed to a heat flux boundary condition to determine the final solution. Results using three different values for r indicate that the value of the constant should vary throughout the domain. A final simulation where r is defined as a function of the streamwise location results in a prediction of the base temperature within 1K of the experimental result, a pressure drop within 30%, and a prediction of the location of transition from subcooled to saturated flow within 2mm.

Two-Phase Flow in Porous Media with Slip Boundary Condition

2008 ◽  
Vol 74 (3) ◽  
pp. 275-292 ◽  
Author(s):  
S. Berg ◽  
A. W. Cense ◽  
J. P. Hofman ◽  
R. M. M. Smits
Keyword(s):  
Boundary Condition ◽  
Porous Media ◽  
Two Phase Flow ◽  
Slip Boundary Condition ◽  
Flow In Porous Media ◽  
Phase Flow ◽  
Two Phase ◽  
Slip Boundary

scholarly journals Simulation of Two Phase Flow Mixing Co – Current in T Junction Using Comsol

2020 ◽  
Vol 21 (1) ◽  
pp. 67-74
Author(s):  
Wallaa A. Noori ◽  
Dhiyaa A. Hussein AlTimimi ◽  
Bashar Jawad Kadhim
Keyword(s):  
Finite Element Method ◽  
Boundary Condition ◽  
Finite Element ◽  
Shear Rate ◽  
Two Phase Flow ◽  
Fluid Dynamic ◽  
Phase Flow ◽  
Cfd Model ◽  
Two Phase ◽  
Flow Mixing

The analysis, behavior of two-phase flow incompressible fluid in T-juction is done by using "A Computational Fluid Dynamic (CFD) model" that application division of different in industries. The level set method was based in “Finite Element method”. In our search the behavior of two phase flow (oil and water) was studed. The two-phase flow is taken to simulate by using comsol software 4.3. The multivariable was studying such as velocity distribution, share rate, pressure and the fraction of volume at various times.  The velocity was employed at the inlet (0.2633, 0.1316, 0.0547 and 0.0283 m/s) for water and (0.1316 m/s) for oil, over and above the pressure set at outlet as a boundary condition. It was observed through the program that the shear rate increased in the mixing area and begins to decrease after the mixing area, for the pressure suddenly decreases in the mixing area and after this area begins to decrease linearly with the length of the tube.

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