ICONE15-10028 TWO-PHASE WALL AND INTERFACIAL FRICTION FORCES IN TRIANGLE TIGHT LATTICE ROD BUNDLE SUBCHANNEL

2007 ◽  
Vol 2007.15 (0) ◽  
pp. _ICONE1510-_ICONE1510
Author(s):  
Akimaro Kawahara ◽  
Michio Sadatomi ◽  
Hiroshi Shirai
Keyword(s):  
Interfacial Friction ◽  
Two Phase ◽  
Friction Forces ◽  
Rod Bundle ◽  
Tight Lattice

scholarly journals Two-Phase Wall and Interfacial Friction Forces in Triangle Tight Lattice Rod Bundle Subchannel

2008 ◽  
Vol 2 (1) ◽  
pp. 283-294 ◽  
Author(s):  
Akimaro KAWAHARA ◽  
Michio SADATOMI ◽  
Hiroshi SHIRAI
Keyword(s):  
Interfacial Friction ◽  
Two Phase ◽  
Friction Forces ◽  
Rod Bundle ◽  
Tight Lattice

Single- and Two-Phase Diversion Cross-Flows Between Triangle Tight Lattice Rod Bundle Subchannels: Data on Flow Resistance and Interfacial Friction Coefficients for the Cross-Flow

2006 ◽  
Author(s):  
Tatsuya Higuchi ◽  
Akimaro Kawahara ◽  
Michio Sadatomi ◽  
Hiroyuki Kudo
Keyword(s):  
Friction Coefficient ◽  
Pressure Difference ◽  
Flow Resistance ◽  
Cross Flow ◽  
Resistance Coefficient ◽  
Interfacial Friction ◽  
Two Phase ◽  
Rod Bundle ◽  
The Cross ◽  
Tight Lattice

Single- and two-phase diversion cross-flows arising from the pressure difference between tight lattice subchannels are our concern in this study. In order to obtain a correlation of the diversion cross-flow, we conducted adiabatic experiments using a vertical multiple-channel with two subchannels simplifying the triangle tight lattice rod bundle for air-water flows at room temperature and atmospheric pressure. In the experiments, data were obtained on the axial variations in the pressure difference between the subchannels, the ratio of flow rate in one subchannel to the whole channel, the void fraction in each subchannel for slug-churn and annular flows in two-phase flow case. These data were analyzed by use of a lateral momentum equation based on a two-fluid model to determine both the cross-flow resistance coefficient between liquid phase and channel wall and the gas-liquid interfacial friction coefficient. The resulting coefficients have been correlated in a way similar to that developed for square lattice subchannel case by Kano et al. (2002); the cross-flow resistance coefficient data can be well correlated with a ratio of the lateral velocity due to the cross-flow to the axial one irrespective of single- and two-phase flows; the interfacial friction coefficient data were well correlated with a Reynolds number, which is based on the relative velocity between gas and liquid cross-flows as the characteristic velocity.

Numerical Simulation of Boiling Two-Phase Flow in Tight-Lattice Rod Bundle by 3-Dimensional Two-Fluid Model Code ACE-3D

2008 ◽  
Author(s):  
Hiroyuki Yoshida ◽  
Takeharu Misawa ◽  
Kazuyuki Takase
Keyword(s):  
Void Fraction ◽  
Lift Force ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Rod Bundle ◽  
Fraction Distribution ◽  
Two Fluid Model ◽  
Tight Lattice ◽  
Two Fluid

Two-fluid model can simulate two phase flow less computational cost than inter-face tracking method and particle interaction method. Therefore, two-fluid model is useful for thermal hydraulic analysis in large-scale domain such as a rod bundle. Japan Atomic Energy Agency (JAEA) develops three dimensional two-fluid model analysis code ACE-3D, which adopts boundary fitted coordinate system in order to simulate complex shape channel flow. In this paper, boiling two-phase flow analysis in a tight lattice rod bundle is performed by ACE-3D code. The parallel computation using 126CPUs is applied to this analysis. In the results, the void fraction, which distributes in outermost region of rod bundle, is lower than that in center region of rod bundle. At height z = 0.5 m, void fraction in the gap region is higher in comparison with that in center region of the subchannel. However, at height of z = 1.1m, higher void fraction distribution exists in center region of the subchannel in comparison with the gap region. The tendency of void fraction to concentrate in the gap region at vicinity of boiling starting point, and to move into subchannel as water goes through rod bundle, is qualitatively agreement with the measurement results by neutron radiography. To evaluate effects of two-phase flow model used in ACE-3D code, numerical simulation of boiling two-phase in tight lattice rod bundle with no lift force model (neglecting lift force acting on bubbles) is also performed. From the comparison of numerical results, it is concluded that the effects of lift force model are not so large on overall void fraction distribution in tight lattice rod bundle. However, higher void fraction distribution in center region of the subchannel was not observed in this simulation. It is concluded that the lift force model is important for local void fraction distribution in rod bundles.

F42 Two-Phase Diversion Cross-Flow between Triangle Tight Lattice Rod Bundle Subchannels

2007 ◽  
Vol 2007.60 (0) ◽  
pp. 219-220
Author(s):  
Tatsuya HIGUCHI ◽  
Shinji MATSUNAGA ◽  
Michio SADATOMI ◽  
Akimaro KAWAHARA
Keyword(s):  
Cross Flow ◽  
Two Phase ◽  
Rod Bundle ◽  
Tight Lattice

Uncertainty Quantification of the RELAP5 Interfacial Friction Model in the Rod Bundle Geometry

2014 ◽  
Author(s):  
Ikuo Kinoshita ◽  
Toshihide Torige ◽  
Minoru Yamada
Keyword(s):  
Model Uncertainty ◽  
Numerical Analyses ◽  
Test Facility ◽  
Interfacial Friction ◽  
Two Phase ◽  
Friction Coefficients ◽  
Oak Ridge ◽  
Rod Bundle ◽  
Separate Effect ◽  
Phase Mixture

An application of the Best Estimate Plus Uncertainty (BEPU) method is made to an analysis of the “Intentional depressurizaion of steam generator secondary side” which is an accident management procedure in a small-break loss-of-coolant accident (SBLOCA) with high pressure injection (HPI) system failure. RELAP5/MOD3.2 is used as the system analysis code. Interfacial friction in the core affects the two-phase mixture level and the distribution of the dispersed gas phase. This phenomenon is very important in terms of the influence its uncertainty has on the peak cladding temperature. The RELAP5/MOD3.2 code uses drift-velocity to describe the interfacial friction coefficients in vertical dispersed flow. The Chexal-Lellouche drift-flux correlation is used for the rod bundle geometry. In the present study, the RELAP5 model uncertainty was quantified regarding the interfacial friction coefficients in the rod bundle geometry by conducting numerical analyses of separate effect tests. As the separate effect tests, two-phase mixture level swell tests in the Thermal Hydraulic Test Facility (THTF) of the Oak Ridge National Laboratory (ORNL) were used. After considering applicability to the SBLOCA, tests were selected for which conditions of pressures and rod powers were similar to PWR plant conditions. A total of 55 data were used. The model uncertainty parameter was defined as a multiplier for the interfacial friction coefficient. Numerical analyses were performed by adjusting the multiplier so that the predicted void fractions agreed with the experimental measured data. The resultant distribution of the multipliers represented the model uncertainty. The mean, standard deviation, minimum and maximum values of this uncertainty distribution were 0.88, 0.55, 0.13 and 3.0, respectively.

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