scholarly journals Visualization of Two-Phase Flow on a Nuclear Power Plant.

1995 ◽  
Vol 9 (4) ◽  
pp. 275-277
Author(s):  
Naohiko HAYASHI
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase

CFD Investigating the Changes of FAC Wear Sites Due to the Power Uprate of Nuclear Power Plant

2009 ◽  
Author(s):  
Tsun Fu Hung ◽  
Yuh Ming Ferng ◽  
Bing Hong Lin ◽  
Chunkuan Shih ◽  
Bau-Shei Pei
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Two Phase Flow ◽  
Control Volume ◽  
Flow Characteristics ◽  
Piping System ◽  
Phase Flow ◽  
Two Phase ◽  
Simulation Results

Changes of flow-accelerated corrosion (FAC) wear sites on the piping due to the power uprate of nuclear power plant are investigated by way of computational fluid dynamics (CFD) models. These models proposed in this paper include the three-dimensional two-phase flow models and appropriate FAC models. The computations are performed using commercial code Fluent 6.2 which is control-volume-based. A boiling water reactor (BWR), located at Taiwan, is selected in the present analytical works. Simulation results clearly reveal that the present model can precisely capture the two-phase phenomena within the piping system. Coupled with the calculated two-phase flow characteristics, the appropriate FAC indictors can predict the local distributions of severe FAC sites. These predicted results show reasonable agreement with the plant measurements. Therefore, the impacts of power uprate on the changes of wear sites can be confidently investigated by the present CFD model. Through the comparisons of predictions for the selected BWRs under 100%, 105%, and 110% power levels, the simulation results clearly reveal that the power uprate does not significantly change the characteristics of FAC wear sites.

Scaling Evaluation of the Two-Phase Natural Circulation

2012 ◽  
Author(s):  
Han Wang ◽  
Yuquan Li
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Characteristic Time ◽  
Nuclear Power ◽  
Natural Circulation ◽  
Scaling Analysis ◽  
Top Down ◽  
Two Phase ◽  
Height Scale ◽  
Full Pressure

This paper presented the scaling evaluation of the two-phase natural circulation process between an assumed nuclear power plant and three test facilities with full pressure simulation and three different height scales, which were 1:2, 1:3 and 1:4. The Hierarchical Two-Tiered Scaling (H2TS) Methodology was adopted. By top-down scaling analysis, several characteristic time ratios were obtained, and then the calculation method of the scaling distortion were investigated. It has been found that the dominant processes in two-phase natural circulation can be well preserved no matter what the height scale is.

Influence of Gas Properties on Gas-Liquid Two-Phase Flow

2020 ◽  
Author(s):  
Miki Saito ◽  
Taizo Kanai ◽  
Satoshi Nishimura ◽  
Yoshihisa Nishi
Keyword(s):  
Removal Efficiency ◽  
Nuclear Power ◽  
Two Phase Flow ◽  
Wire Mesh ◽  
Severe Accident ◽  
Phase Flow ◽  
Stagnant Water ◽  
Two Phase ◽  
Bubble Characteristics ◽  
Gas Properties

Abstract Understanding the mechanism of fission product (FP) removal by pool scrubbing is essential for improving the prediction accuracy of FP emissions concerning severe accident (SA) in a nuclear power plant. Since FP migrates from a gas-phase to a liquid-phase via a gas-liquid interface, the FP removal efficiency by pool scrubbing is largely affected by the flow regime of gas-liquid two-phase flow. In order to gain a deeper understanding of the influence of gas properties on flow regimes, experiments were performed by injecting helium (He) and nitrogen (N2) gas mixtures of several volumetric ratios through a pool of stagnant water. The result suggests clear effects of gas compositions on gas-liquid two-phase flow, where both void and holdup fractions were found to increase with N2 fraction in the supplied gas. The results were compared with previous studies, and a detailed analysis of bubble characteristics for different compositions of gases was performed using a wire-mesh sensor (WMS). This paper also illustrates further research aspects needed to discuss the effect of its results on FP removal efficiency in a SA, and to acquire comprehensive physics behind such gas property influences on two-phase flow.

Design Methodology and Valve Sizing for Heater Drain Systems

2009 ◽  
Author(s):  
Casey Loughrin
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Losses ◽  
Solution Methods ◽  
Flow Phenomena ◽  
Flow Pressure ◽  
And Control

Heater drain systems in fossil and nuclear power plants have proven to be among the most complex systems to design due to the occurrence of two–phase flow phenomena. The overall performance of heater drain systems directly relates to proper sizing and design of the piping and control valves. Proper sizing is highly dependent upon accurate and conservative calculation of two-phase flow pressure losses. This paper outlines the various options of solution methods available to the engineer and details one possible method which is simple, yet adequate, and based on the homogeneous equilibrium model (HEM) for two phase flow for calculation of heater drain system performance. General comparisons are made to the more complex multi-fluid models, flow regime considerations, and non-equilibrium models.

Experimental Research on Steam Jetting and Condensation in Low Sub-Cooled Water

2018 ◽  
Author(s):  
Chunhui Dai ◽  
Mengran Liao ◽  
Qi Xiao ◽  
Jun Wu ◽  
Shaodan Li ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Nuclear Power ◽  
Great Influence ◽  
Low Frequency ◽  
Two Phase ◽  
Noise Characteristics

Steam submerged jetting is an important process in depressurization tank and condenser deaerator tank of nuclear power plant. As the steam contact the liquid water directly, some complicated behaviors such as strong turbulence and phase transition would happens. Especially when the sub-cooling degree is low, the condensation may cause vigorous pressure pulsation and radiation noise, which not only causes noise damage to workers but also affect the safety of the heat exchanger tubes bundle because of vibration transmission. An experiment is proposed to study the complex evolutionary behavior and vibration and noise characteristics of gas-water two-phase flow. The experimental results show that in the case of low subcooling, the mass flow rate of steam has a great influence on gas plume, and, as the mass flow rate increases, the main contribution frequency of noise is gradually increasing from low frequency to high frequency. The researches in this paper can provide the technical basis for the design of the deoxygenation system of condenser in onshore and ship nuclear power plant.

Periodic Oscillations in Natural Circulation Boiling System

2017 ◽  
Author(s):  
Xianbing Chen ◽  
Puzhen Gao ◽  
Qiang Wang ◽  
Yinxing Zhang ◽  
Jiawei Liu
Keyword(s):  
Mass Flux ◽  
Nuclear Power ◽  
Power Plants ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Natural Circulation ◽  
Flow Reversal ◽  
Phase Flow ◽  
Two Phase ◽  
Periodic Oscillations

Natural circulation has been widely used in some evolutionary and innovative nuclear power plants. Natural circulation systems are susceptible to flow instabilities which are undesirable in the nuclear power devices. An experimentally investigation of two phase flow instability in up-flow boing channel under natural circulation is presented in this paper. Flow instability with and without flow reversal have been found. A pulse signal of water temperature at the inlet of the test section can be detected when the channel suffers from flow reversal. Single phase and two phase flow alternate in the channel regardless of the occurrence of flow reversal. Periodic oscillations with multiple high-order harmonic waves are confirmed by applying Fast Fourier Transform to the time traces of flow rates. Period of flow instability which is the reciprocal of the frequency with the largest amplitude in the amplitude-frequency plane are obtained. Period of flow oscillation presents a nonlinear change with the increase of mass flux. Period of flow instability increases rapidly with the increase of mass flux and decreases slowly when it reaches the maximum value.

Sign in / Sign up

Export Citation Format

Share Document