E222 Void Fraction Behavior of Boiling Two-Phase Flow in Horizontal Tube : Numerical Simulation

2009 ◽  
Vol 2009 (0) ◽  
pp. 271-272
Author(s):  
Takeyuki Ami ◽  
Hisashi Umekawa ◽  
Mamoru Ozawa ◽  
Masahiro Shoji
Keyword(s):  
Numerical Simulation ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Horizontal Tube ◽  
Phase Flow ◽  
Two Phase

scholarly journals DYNAMICS OF TWO-PHASE FLOW ACROSS HORIZONTAL TUBE BUNDLES - A REVIEW

2005 ◽  
Vol 4 (2) ◽  
Author(s):  
G. Ribatskia ◽  
J. R. Thome
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Experimental Studies ◽  
Horizontal Tube ◽  
Prediction Methods ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Frictional Pressure Drop ◽  
Tube Bundles

This paper presents a state-of-the-art review of the hydrodynamic aspects of two-phase flow across horizontal tube bundles. The review covers studies related to the evaluation of void fraction, two-phase flow behaviors and pressure drops on the shell side of staggered and in-line tube bundles for upward, downward and side-to-side flows. This study of the literature critically describes the proposed flow pattern maps and semi-empirical correlations for predicting void fraction and frictional pressure drop. These predicting methods are generally based on experimental results for adiabatic air-water flows. A limited number of experimental studies with R-11 and R-113 were also carried out in the past. The review shows noticeable discrepancies among the available prediction methods. Finally, this study suggests that further research focusing on the development of representative databanks and new prediction methods is still necessary.

INVESTIGATION ON VOID FRACTION FOR TWO-PHASE FLOW PRESSURE DROP OF EVAPORATIVE R-290 IN HORIZONTAL TUBE

2016 ◽  
Vol 78 (8-4) ◽  
Author(s):  
Agus Sunjarianto Pamitran ◽  
Sentot Novianto ◽  
Normah Mohd-Ghazali ◽  
Nasruddin Nasruddin ◽  
Raldi Koestoer
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Homogeneous Model ◽  
Saturation Temperature ◽  
Horizontal Tube ◽  
Phase Flow ◽  
Two Phase ◽  
Experimental Conditions

Two-phase flow boiling pressure drop experiment was conducted to observe its characteristics and to develop a new correlation of void fraction based on the separated model. Investigation is completed on the natural refrigerant R-290 (propane) in a horizontal circular tube with a 7.6 mm inner diameter under experimental conditions of 3.7 to 9.6 °C saturation temperature, 10 to 25 kW/m2 heat flux, and 185 to 445 kg/m2s mass flux. The present experimental data was used to obtain the calculated void fraction which then was compared to the predicted void fraction with 31 existing correlations. A new void fraction correlation for predicting two-phase flow boiling pressure drop, as a function of Reynolds numbers, was proposed. The measured pressure drop was compared to the predicted pressure drop with some existing pressure drop models that use the newly developed void fraction model. The homogeneous model of void fraction showed the best prediction with 2% deviation

Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration: (14) Numerical Simulation of Two-Phase Flow in Subchannels Under Accelerating Condition

2014 ◽  
Author(s):  
Hiroyuki Yoshida ◽  
Taku Nagatake ◽  
Kazuyuki Takase ◽  
Akiko Kaneko ◽  
Hideaki Monji ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Nuclear Reactors ◽  
Bubbly Flow ◽  
Flow Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Void Fraction Distribution ◽  
Fraction Distribution

An earthquake is one of the most serious phenomena to consider for the safety of a nuclear reactor in Japan. Therefore, structural safety of nuclear reactors has been studied and nuclear reactors were contracting with structural safety for a big earthquake. However, it is not enough for safety operation of nuclear reactors because thermal-fluid safety is not confirmed under the earthquake. For instance, behavior of gas-liquid two-phase flow is unknown in seismic conditions. Especially, fluctuation of void fraction is an important factor for the safety operation of the nuclear reactor. In previous work, fluctuation of void faction in bubbly flow was studied experimentally and theoretically to investigate the stability of the bubbly flow. In such studies, flow rate or void fraction fluctuations were given to the steady bubbly flow. In case of the earthquake, the fluctuation is not only the flow rate, but also a body force on the two-phase flow and shear force through the pipe wall. Interactions of gas and liquid through their interface also act on the behavior of the two-phase flow. The fluctuation of the void fraction is not clear for such complicated situation during the earthquake. Therefore, the behavior of gas-liquid two-phase flow is investigated experimentally and numerically in a series of studies. In this study, to develop the predictive technology of two-phase flow dynamics under earthquake acceleration, a detailed two-phase flow simulation code with an advanced interface tracking method TPFIT (Two-Phase Flow simulation code with Interface Tracking) was expanded to two-phase flow simulation in seismic conditions. In a previous study, we performed a numerical simulation of a two-phase bubbly flow in a horizontal pipe and a vertical bubble motion in a water tank in seismic conditions. And it was confirmed that the modified TPFIT can be applicable to the bubbly flow in seismic conditions. In this paper, the two-phase bubbly flow in a simulated single-subchannel excited by oscillation acceleration was simulated by using the expanded TPFIT. A calculation domain used in this simulation was a simplified subchannel in a BWR core. And time-series of void fraction distributions were evaluated based on predicted bubble distributions. When no oscillation acceleration was added, void fraction concentrated in a region near the wall. When oscillation acceleration was added, void fraction distribution was changed by time. And coalesces of bubbles occurred in the numerical simulation, and bubbles with relatively large diameter were observed. In the results, complicated void fraction distribution was observed, because the response of void fraction distribution on the oscillation acceleration was dependent on not only imposed acceleration, but also the bubble diameter.

scholarly journals DYNAMICS OF TWO-PHASE FLOW ACROSS HORIZONTAL TUBE BUNDLES - A REVIEW

2005 ◽  
Vol 4 (2) ◽  
pp. 122 ◽  
Author(s):  
G. Ribatskia ◽  
J. R. Thome
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Experimental Studies ◽  
Horizontal Tube ◽  
Prediction Methods ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Frictional Pressure Drop ◽  
Tube Bundles

This paper presents a state-of-the-art review of the hydrodynamic aspects of two-phase flow across horizontal tube bundles. The review covers studies related to the evaluation of void fraction, two-phase flow behaviors and pressure drops on the shell side of staggered and in-line tube bundles for upward, downward and side-to-side flows. This study of the literature critically describes the proposed flow pattern maps and semi-empirical correlations for predicting void fraction and frictional pressure drop. These predicting methods are generally based on experimental results for adiabatic air-water flows. A limited number of experimental studies with R-11 and R-113 were also carried out in the past. The review shows noticeable discrepancies among the available prediction methods. Finally, this study suggests that further research focusing on the development of representative databanks and new prediction methods is still necessary.

STUDY ON NUMERICAL SIMULATION OF VOID FRACTION PROFILE IN LBE TWO-PHASE FLOW

2019 ◽  
Vol 2019.27 (0) ◽  
pp. 2009
Author(s):  
Keisuke MAEDA ◽  
Gen ARIYOSHI ◽  
Daisuke ITO ◽  
Kei ITO ◽  
Yasushi SAITO
Keyword(s):  
Numerical Simulation ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase
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