Research on the Key Technologies of Boiling Flow and Heat Transfer Simulation Based on Two Fluid Model

Author(s):  
Xu Hui-jun
1986 ◽  
Vol 108 (1) ◽  
pp. 100-108 ◽  
Author(s):  
R. C. Dykhuizen ◽  
R. P. Roy ◽  
S. P. Kalra

A linear analysis of dynamic instability in boiling flow systems has been carried out in the time domain. An unequal velocity, unequal temperature two-fluid model description of boiling flow is used. Instability threshold results of the density-wave oscillation type obtained have been compared with experimental data from Refrigerant-113 and water systems with satisfactory agreement.


Author(s):  
Takeharu Misawa ◽  
Hiroyuki Yoshida ◽  
Hidesada Tamai ◽  
Kazuyuki Takase

The three-dimensional two-fluid model analysis code ACE-3D is developed in Japan Atomic Energy Agency for the thermal design procedure on two-phase flow thermal-hydraulics of light water-cooled reactors. In order to perform thermal hydraulic analysis of SCWR, ACE-3D is enhanced to supercritical pressure region. As a result, it is confirmed that transient change in subcritical and supercritical pressure region can be simulated smoothly using ACE-3D, that ACE-3D can predict the results of the past heat transfer experiment in the supercritical pressure condition, and that introduction of thermal conductivity effect of the wall restrains fluctuation of wall.


Author(s):  
Tingting Ren ◽  
Changqi Yan ◽  
Meiyue Yan ◽  
Shengzhi Yu

Two-fluid model is a common method to simulate the subcooled flow boiling heat transfer, in which the wall boiling model is mainly used for the partition of wall heat flux and the mass transfer between two phases on the wall. The model determines the amount of vapor phase and predicts the cross-sectional void fraction in the channel, nucleate site density and bubble departure diameter play an important role in the accurate prediction of wall boiling model. Eulerian two-fluid model coupled with Rensselaer Polytechnic Institute (RPI) wall boiling model is employed to simulate the heat transfer characteristics and boiling phenomena in vertical narrow rectangular channels by using FLUENT code. Based on the experimental data of subcooled boiling in vertical narrow rectangular channel, different combinations of nucleate site density and bubble departure diameter correlations are used to calculate under different conditions of heat flux and inlet subcooling. Comparing the calculated heat transfer coefficients along the vertical height with experimental results, it can be found that these two parameters have a significant effect on the subcooled boiling heat transfer in narrow rectangular channels. Different parameter combinations lead to differences in wall heat flux distribution, different heat flux and inlet subcooling also have different effects on these models, which eventually lead to different evaporative heat flux, thus affecting the prediction of void fraction.


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