A Large-Scale Numerical Simulation on Bubbly and Liquid Film Flows in Narrow Fuel Channels

2005 ◽  
Author(s):  
K. Takase ◽  
H. Yoshida ◽  
Y. Ose ◽  
H. Akimoto
Keyword(s):  
Large Scale ◽  
Two Phase Flow ◽  
Reactor Core ◽  
Light Water Reactor ◽  
Phase Flow ◽  
Analysis Method ◽  
Two Phase ◽  
Light Water ◽  
Water Reactor ◽  
Fuel Bundle

In order to predict the water-vapor two-phase flow structure in a fuel bundle of an advanced light-water reactor, large-scale numerical simulations were carried out using a newly developed two-phase flow analysis method and a highly parallel-vector supercomputer. Conventional analysis methods such as subchannel codes need composition equations based on many experimental data. Therefore, it is difficult to obtain highly prediction accuracy on the thermal design of the advanced light-water reactor core if the experimental data are insufficient. Then, a new analysis method using the large-scale direct numerical simulation of water-vapor two-phase flow was proposed. The coalescence and fragmentation of small bubbles were investigated numerically and the bubbly flow dynamics in narrow fuel channels were clarified. Moreover, the liquid film flow inside a tight-lattice fuel bundle which is used to the advanced light-water reactor core was analyzed and the water and vapor distributions around fuel rods and a spacer were estimated quantitatively.

Development of Quantitative Analytical Procedures on Two-Phase Flow in Tight-Lattice Fuel Bundles for Reduced-Moderation Light-Water Reactors

2004 ◽  
Author(s):  
Kazuyuki Takae ◽  
Hiroyuki Yoshida ◽  
Masatoshi Kureta ◽  
Hidesada Tamai ◽  
Akira Ohnuki ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Conversion Ratio ◽  
Thermal Design ◽  
Phase Flow ◽  
Two Phase ◽  
Light Water ◽  
Water Reactor ◽  
Model Experiments ◽  
Analytical Procedures ◽  
Tight Lattice

R&D project to investigate thermal-hydraulic performance in tight-lattice rod bundles for Reduced-Moderation Water Reactor (RMWR) has started at Japan Atomic Energy Research Institute (JAERI) in collaboration with power companies, reactor vendors, universities since 2002. The RMWR is a light water reactor which a higher conversion ratio more than one can be expected. In order to attain this higher conversion ratio, triangular tight-lattice fuel bundles which gap spacing between each fuel rod is around 1 mm are required. As for the thermal design of the RMWR core, conventional analytical methods are no good because the conventional composition equations can not predict the RMWR core with high accuracy. Then, development of new quantitative analytical procedures was carried out. Those analytical procedures are constructed by model experiments and advanced two-phase flow analysis codes. This paper describes the results of the model experiments and analytical results with the developed analysis codes.

A Large-Scale Simulation on Two-Phase Flow Characteristics Around Duel Rods in a Tight-Lattice Core

2006 ◽  
Author(s):  
K. Takase ◽  
H. Yoshida ◽  
Y. Ose ◽  
H. Akimoto
Keyword(s):  
Large Scale ◽  
Two Phase Flow ◽  
Water Film ◽  
Axial Position ◽  
Phase Flow ◽  
Two Phase ◽  
Fuel Rods ◽  
Fuel Rod ◽  
Fuel Bundle ◽  
Tight Lattice

Water-vapor two-phase flow structure in a fuel bundle of an advanced light water reactor was analyzed numerically by large-scale direct simulations. A newly developed two-phase flow analysis code was used. It can precisely predict the interface behavior between the liquid and gas phase by using the interface tracking method. The present analytical geometry simulates a tight-lattice fuel bundle with 37 fuel rods and four spacers. The fuel rod outer diameter is 13 mm and gap spacing between each rod is 1.3 mm. Each spacer is installed in an arbitrary axial position in order to keeping the gap width. Water flows upward from the bottom of the fuel bundle. The inlet conditions of water are as follows: temperature 283°C, pressure 7.2 MPa, flow rate 400 kg/m2s, and the Reynolds number 40,000. In the present study three-dimensional computations were carried out under the non-heated isothermal flow condition in order to remove the effect of heat transfer by the fuel rods. The average mesh size in the present numerical study was 0.15 mm. From results of a series of the numerical simulations, the following consideration was derived: 1)The fuel rod surface is encircled with thin water film; 2)The bridge phenomenon by the water film appears in the region where the spacing between fuel rods is narrow; 3)Vapor flows downward the triangular region where the spacing between fuel rods is large; and, 4)A flow configuration of vapor shows the streak structure in the vertical direction.

TWO-PHASE FLOW INSTABILITIES ANALYSES IN BOILING WATER REACTOR

2016 ◽  
Author(s):  
Antonella Lombardi Costa ◽  
WILMER ARUQUIPA COLOMA ◽  
Antonella Lombardi Costa ◽  
Claubia Pereira ◽  
Maria Veloso ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Boiling Water ◽  
Flow Instabilities ◽  
Boiling Water Reactor ◽  
Phase Flow ◽  
Two Phase ◽  
Water Reactor

Surveillance Models of Large-Scale ESP With High Viscosity Fluids and Gas

2012 ◽  
Author(s):  
Lissett Barrios ◽  
Stuart Scott ◽  
Charles Deuel
Keyword(s):  
Large Scale ◽  
Two Phase Flow ◽  
Electrical Current ◽  
High Viscosity ◽  
Viscous Fluids ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Operational Parameters ◽  
Two Phase ◽  
Operational Conditions

The paper reports on developmental research on the effects of viscosity and two phases, liquid–gas fluids on ESPs which are multi stage centrifugal pumps for deep bore holes. Multiphase viscous performance in a full-scale Electrical Submersible Pump (ESP) system at Shell’s Gasmer facility has been studied experimentally and theoretically. The main objectives is to predict the operational conditions that cause degradations for high viscosity fluids when operating in high Gas Liquid Radio (GLR) wells to support operation in Shell major Projects. The system studied was a 1025 series tandem WJE 1000. The test was performed using this configuration with ten or more pump stages moving fluids with viscosity from 2 to 200 cP at various speed, intake pressure and Gas Void Fractions (GVF). For safety considerations the injected gas was restricted to nitrogen or air. The ESP system is a central artificial lift method commonly used for medium to high flow rate wells. Multiphase flow and viscous fluids causes problems in pump applications. Viscous fluids and free gas inside an ESP can cause head degradation and gas locking. Substantial attempts have been made to model centrifugal pump performance under gas-liquid viscous applications, however due to the complexity this is still a uncertain problem. The determination of the two-phase flow performance in these harmful conditions in the ESP is fundamental aspects in the surveillance operation. The testing at Shell’s Gasmer facility revealed that the ESP system performed as theoretical over the range of single flowrates and light viscosity oils up to Gas Volume Fractions (GVF) around 25%. The developed correlations predict GVF at the pump intake based on the operational parameters. ESP performance degrades at viscosity higher than 100cp as compared to light oil applications, gas lock condition is observed at gas fraction higher than 45%. Pump flowrate can be obtained from electrical current and boost for all range of GVF and speed. The main technical contributions are the analysis of pump head degradation under two important variables, high viscosity and two-phase flow inside the ESP.

Development of Analytical Procedures of Two-Phase Flow in Tight-Lattice Fuel Bundles for Innovative Water Reactor for Flexible Fuel Cycle

2008 ◽  
Vol 164 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Hiroyuki Yoshida ◽  
Akira Ohnuki ◽  
Takeharu Misawa ◽  
Kazuyuki Takase ◽  
Hajime Akimoto
Keyword(s):  
Two Phase Flow ◽  
Fuel Cycle ◽  
Phase Flow ◽  
Two Phase ◽  
Water Reactor ◽  
Analytical Procedures ◽  
Tight Lattice
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