Numerical Simulation of the Interfacial Growth of the Stratified Wavy Two-Phase Flow in the Horizontal Rectangular Channel

2004 ◽  
Author(s):  
Ken-ichi Ebihara ◽  
Tadashi Watanabe
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Channel Width ◽  
Phase Flow ◽  
Dimensionless Numbers ◽  
Two Phase ◽  
Flow Pattern Map ◽  
Interfacial Growth

Two-phase flow is one of the important phenomena that are found in nuclear reactors. It is required for the design and the safe operation of nuclear reactors to understand and predict the two-phase flow phenomenon by numerical analyses. This paper describes the numerical simulation of the interfacial growth of the stratified wavy two-phase flow in the horizontal rectangular channel. This flow is the cocurrent flow separated by gravity and a fundamental flow pattern of two-phase flow. The influence of the channel width upon the growth of the interfacial wave was evaluated by carrying out several simulations for the different channel width. The numerical simulation model adopted in this paper is a one-component two-phase fluid model of the lattice Boltzmann method. This model has been developed and utilized for numerical analyses of two-phase flow in recent years because it has the capability of simulating spontaneous phenomena of the interface between phases. The wave growth was observed and the dimensionless numbers that characterize the two-phase flow state were measured during the computations. The relation between the wave growth and the dimensionless numbers, which were obtained as the computational results was compared with that in the flow pattern map proposed on the basis of theoretical consideration by Taitel and Dukler. It was verified in the case of the wide channel width that the simulated relation was in agreement with that in the theoretical flow pattern map. It was shown that the narrower the channel width became, the more mass flow rate of the rare phase the interfacial growth needed and the obtained relation deviated from that in the flow pattern map.

Flow Boiling in Horizontal Tubes: Part 1—Development of a Diabatic Two-Phase Flow Pattern Map

1998 ◽  
Vol 120 (1) ◽  
pp. 140-147 ◽  
Author(s):  
N. Kattan ◽  
J. R. Thome ◽  
D. Favrat
Keyword(s):  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Parameters ◽  
Horizontal Tubes ◽  
Flow Pattern Map ◽  
Wide Range ◽  
Data Points

An improved two-phase flow pattern map is proposed for evaporation in horizontal tubes. The new map was developed based on flow pattern data for five different refrigerants covering a wide range of mass velocities and vapor qualities. The new map is valid for both adiabatic and diabatic (evaporating) flows and accurately identifies about 96 percent of the 702 data points. In addition, the new flow pattern map includes the prediction of the onset of dryout at the top of the tube during evaporation inside horizontal tubes as a function of heat flux and flow parameters.

Comparison of experimental data and numerical simulation of two-phase flow pattern in vertical minichannel

2012 ◽  
Vol 33 (1) ◽  
pp. 63-71
Author(s):  
Jarosław Sowiński ◽  
Marek Krawczyk ◽  
Marek Dziubiński
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Boundary Conditions ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Computational Domain ◽  
Two Phase ◽  
Ansys Fluent ◽  
Satisfactory Description

Comparison of experimental data and numerical simulation of two-phase flow pattern in vertical minichannel The aim of the study was the implementation of a numerical simulation of the air-water two-phase flow in the minichannel and comparing results obtained with the values obtained experimentally. To perform the numerical simulations commercial software ANSYS FLUENT 12 was used. The first step of the study was to reproduce the actual research installation as a three-dimensional model with appropriate and possible simplifications - future computational domain. The next step was discretisation of the computational domain and determination of the types of boundary conditions. ANSYS FLUENT 12 has three built-in basic models with which a two-phase flow can be described. However, in this work Volume-of-Fluid (VOF) model was selected as it meets the established requirements of research. Preliminary calculations were performed for a simplified geometry. The calculations were later verified whether or not the simplifications of geometry were chosen correctly and if they affected the calculation. The next stage was validation of the chosen model. After positive verification, a series of calculations was performed, in which the boundary conditions were the same as the starting conditions in laboratory experiments. A satisfactory description of the experimental data accuracy was attained.

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