Numerical Simulation of Steam Generator Tube Rupture Sequence in ADS Reactor

2014 ◽  
Author(s):  
Xu Yang ◽  
Tao Zhou ◽  
Daping Lin ◽  
Xiaolu Fang ◽  
Baixu Chen ◽  
...  
Keyword(s):  
Steam Generator ◽  
Continuous Phase ◽  
Discrete Phase Model ◽  
Primary Coolant ◽  
Steam Generator Tube ◽  
Spallation Target ◽  
Steel Material ◽  
Stainless Steel Material ◽  
Discrete Phase ◽  
Secondary Side

In ADS reactor which choose LBE (Lead-Bismuth Eutectic) as coolant and spallation target. While SGTR (Steam Generator Tube Rupture) accident occur, water in secondary side will inject to LBE in primary coolant, and flow with LBE. The code of FLUENT will be used, steam is looked as particle, and standard k-ε model is used to predict turbulence variation of continuous phase in core. The DPM (Discrete Phase Model) will be used to track the trajectory of the particles. The distribution of steam in core will be obtained, which will verify the safety of reactor. The results show that the steam flowing across the core with LBE, might accumulate in some position and cause a surge of power. At the same time, the aggregation of steam at the channel might lead to a steam plug, and hinder the flow of the coolant in core, then core overheating might occur. Last but not least, local accumulation of water vapor may accelerate the corrosion of stainless steel material in core.

Numerical Study of the Deposition of Radioactive Nucleoids (Aerosol) in PWR Steam Generator

2021 ◽  
Author(s):  
Muhammad Aadil ◽  
Rab Nawaz ◽  
Ajmal Shah ◽  
Kamran Rasheed Qureshi
Keyword(s):  
Steam Generator ◽  
Numerical Study ◽  
Deposition Efficiency ◽  
Decontamination Factor ◽  
Radioactive Nuclide ◽  
Discrete Phase Model ◽  
Velocity Magnitude ◽  
Discrete Phase ◽  
Steam Generator Tubes ◽  
Secondary Side

Abstract This research presents numerical study of deposition efficiency and decontamination factor of radioactive nuclide in steam generator tubes of a typical 325 MWe PWR. To find out the deposition of aerosol, the discrete phase model (DPM) has been used. The flow has been characterized as compressible, adiabatic, turbulent and wall bounded. When steam generator tube gets ruptured, the radioactive nuclides can escape from primary side and create a radioactive field in the secondary side. This can be harmful for the personnel working at the plant. Therefore, in order to ensure the safety of the plant and personnel, it is important to study the particles deposition on the wall of steam generator tubes. In the present study, a CFD methodology has been first developed and validated with the published results. After methodology validation, it has been applied to the U-tube of a typical PWR steam generator. It has been observed that due to the action of centrifugal force near the bent, the velocity magnitude is high towards the inner wall and the flow separates at the bent entrance. Furthermore, the flow inside the tube is rotational with vortices throughout the domain due to the presence of the bent. Finally, the deposition efficiency and decontamination factor have been calculated and it has been observed that both increase with the increase in particle size due to inertial effects.

scholarly journals Effects of Blade Parameters on the Flow Field and Classification Performance of the Vertical Roller Mill via Numerical Investigations

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chang Liu ◽  
Zuobing Chen ◽  
Weili Zhang ◽  
Chenggang Yang ◽  
Ya Mao ◽  
...  
Keyword(s):  
Flow Field ◽  
Pressure Difference ◽  
Continuous Phase ◽  
Classification Performance ◽  
Field Analysis ◽  
Discrete Phase Model ◽  
Roller Mill ◽  
Discrete Phase ◽  
Vertical Roller ◽  
Classification Efficiency

The vertical roller mill is an important crushing and grading screening device widely used in many industries. Its classification efficiency and the pressure difference determine the entire producing capacity and power consumption, respectively, which makes them the two key indicators describing the mill performance. Based on the DPM (Discrete Phase Model) and continuous phase coupling model, the flow field characteristics in the vertical roller mill including the velocity and pressure fields and the discrete phase distributions had been analyzed. The influence of blade parameters like the shape, number, and rotating speed on the flow field and classification performance had also been comprehensively explored. The numerical simulations showed that there are vortices in many zones in the mill and the blades are of great significance to the mill performance. The blade IV not only results in high classification efficiency but also reduces effectively the pressure difference in the separator and also the whole machine. The conclusions of the flow field analysis and the blade effects on the classification efficiency and the pressure difference could guide designing and optimizing the equipment structure and the milling process, which is of great importance to obtain better overall performance of the vertical roller mill.

Unsteady Modeling of Powdered Activated Carbon Deposition on Collection Electrode of a Lab-Scale Electrostatic Precipitator (ESP)

2012 ◽  
Author(s):  
Yasmin Khakpour ◽  
Herek L. Clack
Keyword(s):  
Activated Carbon ◽  
Particle Deposition ◽  
Electrostatic Precipitator ◽  
Activated Carbons ◽  
Collection Efficiency ◽  
Continuous Phase ◽  
Powdered Activated Carbon ◽  
Computational Domain ◽  
Discrete Phase Model ◽  
Discrete Phase

Particulate sampling in the flue gas at the Electrostatic Precipitator (ESP) outlet during injection of powdered activated carbons (PACs) has provided strong anecdotal evidence indicating that injected PACs can penetrate the ESP in significant concentrations. The low resistivity of PAC is consistent with poor collection efficiency in an ESP and lab-scale testing has revealed significantly different collection behavior of PAC in an ESP as compared to fly ash. The present study illustrates the use of a commercial CFD package — FLUENT — to investigate precipitation of powdered activated carbon (PAC) in the presence and absence of electric field. The computational domain is designed to represent a 2-D wire-plate ESP channel. The governing equations include those covering continuous phase transport, electric potential, air ionization, and particle charging. The particles are tracked using a Lagrangian Discrete Phase Model (DPM). In addition, a custom user-defined function (UDF) uses a deforming boundary condition and a prescribed critical particle velocity to account for particle deposition and dust-cake growth on the electrodes. The effect of Electrohydrodynamics (EHD) induced flow on the ESP collection efficiency under various flow and particle characteristics as well as different ESP configurations are illustrated.

CFD Study on must of Grapes Separation in a Hydrocyclone

2013 ◽  
Vol 837 ◽  
pp. 645-650
Author(s):  
Petru Cârlescu ◽  
Ioan Tenu ◽  
Marius Baetu ◽  
Radu Rosca
Keyword(s):  
Cfd Simulation ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Solid Particles ◽  
Advanced Degree ◽  
Separation And Purification ◽  
Discrete Phase Model ◽  
Flow Rates ◽  
Discrete Phase ◽  
Simulation And Experiment

Abstract. Hydrocyclones are increasingly used in the food industry for various separation and purification. In this paper, an optimization was made to design a hydrocyclone model using CFD (Computational Fluid Dynamics). CFD simulation is performed with FLUENT software by coupling the Reynolds Stress Model (RSM) for must of grapes flow with Discrete Phase Model (DPM) for solid particles trajectory. Coupling of discrete phase (particles) and continuous phase (must of grapes) in the mathematical model is set so that the continuous phase to influence discrete phase. Tracking particles traiectory in this hydrocyclone allows advanced degree is separation so obtained to the maximum particle size approaching the size of a yeast cell 10 μm, without separating them. Hydrocyclone dimensional designed simulation was performed and analyzed on an experimental pilot plant for three different must flow rates supply. Introduced particle flow rates simulation and experiment does not exceed 10% of the must flow rates. The degree of separation obtained is in agreement with experimental data.

The PSI Artist Project: Aerosol Retention and Accident Management Issues Following a Steam Generator Tube Rupture

2002 ◽  
Author(s):  
Salih Gu¨ntay ◽  
Abdel Dehbi ◽  
Detlef Suckow ◽  
Jon Birchley
Keyword(s):  
Steam Generator ◽  
Tube Bundle ◽  
Severe Accident ◽  
Pressurized Water ◽  
Steam Generator Tube ◽  
Full Size ◽  
Management Actions ◽  
Accident Management ◽  
Dry Conditions ◽  
Secondary Side

Steam generator tube rupture (SGTR) incidents, such as those, which occurred in various operating pressurized, water reactors in the past, are serious operational concerns and remain among the most risk-dominant events. Although considerable efforts have been spent to understand tube degradation processes, develop improved modes of operation, and take preventative and corrective measures, SGTR incidents cannot be completely ruled out. Under certain conditions, high releases of radionuclides to the environment are possible during design basis accidents (DBA) and severe accidents. The severe accident codes’ models for aerosol retention in the secondary side of a steam generator (SG) have not been assessed against any experimental data, which means that the uncertainties in the source term following an unisolated SGTR concurrent with a severe accident are not currently quantified. The accident management (AM) procedures aim at avoiding or minimizing the release of fission products from the SG. The enhanced retention of activity within the SG defines the effectiveness of the accident management actions for the specific hardware characteristics and accident conditions of concern. A sound database on aerosol retention due to natural processes in the SG is not available, nor is an assessment of the effect of management actions on these processes. Hence, the effectiveness of the AM in SGTR events is not presently known. To help reduce uncertainties relating to SGTR issues, an experimental project, ARTIST (AeRosol Trapping In a Steam generaTor), has been initiated at the Paul Scherrer Institut to address aerosol and droplet retention in the various parts of the SG. The test section is comprised of a scaled-down tube bundle, a full-size separator and a full-size dryer unit. The project will study phenomena at the separate effect and integral levels and address AM issues in seven distinct phases: Aerosol retention in 1) the broken tube under dry secondary side conditions, 2) the near field close to break under dry conditions, 3) the bundle far-field under dry conditions, 4) the separator and dryer under dry conditions, 5) the bundle section under wet conditions, 6) droplet retention in the separator and dryer sections and 7) the overall SG (integral tests). Prototypical test parameters are selected to cover the range of conditions expected in severe accident as well as DBA scenarios. This paper summarizes the relevant issues and introduces the ARTIST facility and the provisional test program which will run between 2003 and 2007.

Aerodynamic Characteristics of NACA 23015 Landing Configuration with 20o Flap in Simulated Rain

2014 ◽  
Vol 555 ◽  
pp. 108-112
Author(s):  
Shahid Latif ◽  
Zhou Hong ◽  
Muhammad Ismail
Keyword(s):  
Heavy Rain ◽  
Aerodynamic Characteristics ◽  
Continuous Phase ◽  
Phase Flow ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Discrete Phase Modeling ◽  
Wall Film ◽  
Discrete Phase ◽  
Simulated Rain

In our numerical simulation the heavy rain effects have been studied on the aerodynamic performance of 2D cambered NACA 23015 airfoil landing configuration with 20o. We have used preprocessing software gridgen for creation of the landing configuration of the airfoil and then creating mesh around it. Fluent is used to solve the conservation equations. We have used discrete phase modeling (DPM) in Fluent to simulate the rain phenomenon in continuous phase flow by using two phase flow approach. In our study the coupling between the discrete and the continuous phase has been activated. In discrete phase model (DPM), we used the wall film model for the interaction of the continuous and discrete phase. The airfoil landing configuration exhibited significant decrease in lift and increase in drag for a given lift conditions in simulated rain. Post processing software like MATLAB, Tec plot and Origin are used to see the effects of the heavy rain and then results obtained are compared with the experimental results. Our numerical results in most of cases show similar trends with the experiments.

scholarly journals The Experimental Study on Effects of Height and Hold up on performance of Vertical Gas-Liquid Separator using Amin Contactor Tower

2015 ◽  
Vol 37 ◽  
pp. 93 ◽  
Author(s):  
Iman Naderipour ◽  
Jamshid Khorshidi
Keyword(s):  
Liquid Droplet ◽  
Three Dimensional ◽  
Continuous Phase ◽  
Three Dimension ◽  
Liquid Droplets ◽  
Discrete Phase Model ◽  
Effective Parameters ◽  
Discrete Phase ◽  
Droplet Tracking ◽  
Liquid Separator

In present research, first the treatment of flow in designed vertical gas-liquid separator and Amin contactor tower at refinery in order to reduce of liquid percent was simulated. In order to simulation was used three dimension model with finite volume method numerically. Then separator and contactor tower has been modeled three dimensional and for droplet tracking in continuous phase has been used discrete phase model (DPM) with turbulence RNG k-Ɛ model. Also the gambit software is used for three dimension designs and fluent is used for solution governing equations of flow field. After simulation, the governing model of separator and contactor tower, fluid flow, the effect of growing of liquid droplet, droplet settling length (disengagement time) was studied. After analysis and compare behavior of flow in separator and tower, the results of simulation compared with experimental results at sweetening unit in Sarkhoun and Qeshm gas treating company that has 95% compatibility. The simulation results has shown that TOTAL method has more compatibility with relation to other methods so that one of effective parameters in improvement of separation process is growing of liquid droplets and separation factor depend on that, also more disengagement time causes increase hold up time and finally growing of liquid droplets. Additionally according to younger's comment gas-liquid separators can applied in horizontal or vertical status so that he founded if L/D be 1.7 to 3.6, the separators should be used vertically also Branan has proved that if L/D > 5, a horizontal separator should be used. The results of research are shown that in special conditions with L/D>6.5 can apply vertical separator. Finally experimental data has shown that the settling length can be 36 ft (11m) that separation works well and according to Schiman this length should be 0.75D or a minimum 12in (0.305 m) whereas Gerunda recommends a length equal to the diameter or a minimum of 3 ft (0.914 m) that present result is new recommendation.

scholarly journals Study on Performance of Mesoscopic Impactor Filters for Aerosol Removal

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Zhang ◽  
Fenglei Niu ◽  
Shiji Wang ◽  
Haonan Wang ◽  
Zhangpeng Guo
Keyword(s):  
Collection Efficiency ◽  
Fluid Dynamic ◽  
Structural Parameters ◽  
Continuous Phase ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
Small Flow ◽  
Cfd Method ◽  
Working Parameters ◽  
Design And Manufacture

The mesoscopic impactor filter is designed to filtrate aerosols in the containment, which has not only high collection efficiency but also small flow resistance. In this paper, the influence of structural parameters and working parameters of the inertial impactor on collection performance is studied by the computational fluid dynamic (CFD) method. Under the small Reynolds number, the laminar model is used to simulate the continuous phase, and the discrete phase model (DPM) is used to track the trajectory of the particle. Based on the response surface methodology (RSM), the prediction model of collection efficiency and pressure drop is obtained, which will provide a reference for the design and manufacture of the filter in the future.

Experimental and Theoretical Analysis of Subcooled Water Discharge Through Simulated Steam Generator Tube Cracks

2013 ◽  
Author(s):  
Shripad T. Revankar ◽  
Ram Anand Vadlamani ◽  
Jovica R. Riznic
Keyword(s):  
Steam Generator ◽  
Water Discharge ◽  
Boundary Surface ◽  
Two Phase ◽  
Primary Coolant ◽  
Pressurized Water ◽  
Steam Generator Tube ◽  
Water Reactor ◽  
Homogeneous Equilibrium ◽  
Non Equilibrium

The steam generator (SG) tubes represent a major fraction of the reactor primary coolant pressure boundary surface area in both Canadian pressurized heavy water reactor (CANDU) reactors and pressurized water reactor (PWR). There is very limited data on the steam generator tube leak rate measurement. Most studies of subcooled choking flow are related to long tubes with L/D greater than 15. Also, all of those data have a channel length greater than 10 mm, which is not indicative of steam generator tubing. Steam generator tubes have a wall thickness typically less than 3 mm. Experiments were conducted on choking flow for various simulated crack geometries for vessel pressures up to 7 MPa with various subcoolings. Measurements were done on subcooled flashing flow rate through well defined simulated crack geometries with L/D at ∼2 and 5–6. Both homogeneous equilibrium and non-equilibrium mechanistic models were developed to model two-phase choking flow through slits. A comparison of the model results with experimental data shows that the homogeneous equilibrium based models grossly under predict choking flow rates in such geometries, while homogeneous non-equilibrium models greatly increase the accuracy of the predictions.

Study on the Modeling and Simulation of the Horizontal Steam Generator in VVER-1000

2021 ◽  
Author(s):  
Ru Zhang ◽  
Junyan Qing ◽  
Xiaolong Bi ◽  
Guanfu Jiang ◽  
Peiwei Sun ◽  
...  
Keyword(s):  
Steam Generator ◽  
Nuclear Power ◽  
Tube Bundle ◽  
Natural Circulation ◽  
Thermal Power ◽  
Secondary Circuit ◽  
Primary Coolant ◽  
Pressurized Water ◽  
Horizontal Steam Generator ◽  
Secondary Side

Abstract Steam Generator (SG) is one of the main components of the power cycle in pressurized water reactor (PWR), and it is the hub of primary coolant circuit and secondary circuit, so the thermal hydraulic analysis of the SG is crucial in the system design and safety analysis of the PWR. The horizontal steam generator (HSG) is one of the main types SG in the PWR nuclear power plant (NPP), and its advantages are that it has more secondary side water capacity and good safety and reliability. The VVER-1000 is a PWR with a thermal power of 3000 MW, and has four HSGs for four loops. The RELAP5 has been used to model the VVER-1000’s HSG and performs the analysis described in this paper. The HSG tube bundle is modeled by three horizontal channels, and the steam control volumes above the heat transfer tube bundle are modeled with three volumes. The steam space is modeled as a steam separator and the steam reception shield is the dryer. The HSG secondary side downcomers are represented with a separate component to provide the power of the natural circulation. To verify the accuracy of the model, three different typical conditions are simulated. The simulation results show that the model built in this paper can correctly simulate the operation of the HSG in VVER-1000.

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