A calculation method for transient flow distribution of SCWR(CSR1000)

2017 ◽  
Vol 110 ◽  
pp. 541-546 ◽  
Author(s):  
Juan Chen ◽  
Tao Zhou ◽  
Jie Chen ◽  
Liang Liu ◽  
Ali Shahzad Muhammad ◽  
...  
Keyword(s):  
Calculation Method ◽  
Transient Flow ◽  
Flow Distribution

scholarly journals Dynamic Modeling and Flow Distribution of Complex Micron Scale Pipe Network

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 763
Author(s):  
Yao Zhao ◽  
Kai Zhang ◽  
Fengbei Guo ◽  
Mingyue Yang
Keyword(s):  
Calculation Method ◽  
Flow Distribution ◽  
Microfluidic Devices ◽  
Active Role ◽  
Fluid Simulation ◽  
Electrical Method ◽  
Fluid Network ◽  
Microfluidic Network ◽  
Simulation Calculation ◽  
Length Changes

A fluid simulation calculation method of the microfluidic network is proposed as a means to achieve the flow distribution of the microfluidic network. This paper quantitatively analyzes the influence of flow distribution in microfluidic devices impacted by pressure variation in the pressure source and channel length. The flow distribution in microfluidic devices with three types of channel lengths under three different pressure conditions is studied and shows that the results obtained by the simulation calculation method on the basis of the fluid network are close to those given by the calculation method of the conventional electrical method. The simulation calculation method on the basis of the fluid network studied in this paper has computational reliability and can respond to the influence of microfluidic network length changes to the fluid system, which plays an active role in Lab-on-a-chip design and microchannel flow prediction.

Methodology Development for Transient Flow Distribution Analysis in High Temperature Gas-Cooled Reactor

2020 ◽  
Author(s):  
Takeshi Aoki ◽  
Hiroyuki Sato ◽  
Hirofumi Ohashi
Keyword(s):  
High Temperature ◽  
Hydraulic System ◽  
System Analysis ◽  
Molecular Diffusion ◽  
Transient Flow ◽  
Flow Distribution ◽  
Distribution Analysis ◽  
Design Improvement ◽  
Air Ingress ◽  
High Temperature Gas

Abstract In the thermal hydraulic design of the prismatic-type of the high temperature gas cooled reactor (HTGR), unintended flows such as gap flows between columns, cross flows between column layers and gap flows between permanent reflectors should be analyzed to minimizing the unintended flows. The flow distribution considering unintended flows in the reactor has been evaluated for steady and conservative condition. On the other hand, the transient thermal hydraulic analysis for satisfactorily realistic conditions will be helpful for the design improvement of prismatic-type HTGR. The present study aims to improve the thermal hydraulic system analysis code developed by Japan Atomic Energy Agency based on the RELAP5/MOD3 code and confirm its applicability for the transient flow distribution analysis for prismatic-type HTGRs during anticipated operational occurrences and accidents for its design improvement utilizing experiences on high temperature engineering test reactor (HTTR) design. The calculation model and code were developed and validated to evaluate the detailed flowrate distribution considering the unintended flows in the core and the molecular diffusion that is important to analyze beginning air ingress behavior in an air ingress accident triggered by a rupture of a primary coolant piping in HTGR. It is concluded that a prospect has confirmed to apply the improved thermal hydraulic system analysis code for transient flow distribution analysis for prismatic-type HTGRs.

Modeling the Thermally Governed Transient Flow Surges in Multitube Condensing Flow Systems With Thermal and Flow Distribution Asymmetry

1989 ◽  
Vol 111 (3) ◽  
pp. 786-791 ◽  
Author(s):  
G. L. Wedekind ◽  
B. L. Bhatt
Keyword(s):  
Flow Rate ◽  
Transient Flow ◽  
Liquid Flow Rate ◽  
Flow Distribution ◽  
Vapor Flow ◽  
Tube Model ◽  
Condenser Tube ◽  
Tube System ◽  
Tube Type ◽  
Complete Condensation

In a tube-type condenser involving complete condensation, small changes in the inlet vapor flow rate momentarily cause very large transient surges in the outlet liquid flow rate. An equivalent single-tube model is proposed that predicts these transient flow surges for a multitube system. The model, based upon a system mean void fraction model developed earlier, includes the effects of thermal and flow distribution asymmetry associated with each individual condenser tube in the multitube system. Theoretical and experimental verification for a two-tube system is presented.

THE FORMALIZATION OF VARIATIONAL PROBLEM MODELING IN THE CURRENT DISTRIBUTION IN THE SAFE OPERATION OF HYDRAULIC SYSTEMS

2016 ◽  
Vol 8 (4) ◽  
pp. 46-49
Author(s):  
Мезенцев ◽  
A. Mezentsev ◽  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Mathematical Models ◽  
Variational Problem ◽  
Current Distribution ◽  
Hydraulic System ◽  
Transient Flow ◽  
Flow Distribution ◽  
Safety Performance ◽  
System Of Equations ◽  
Hydraulic Systems ◽  
Safe Operation

For the calculated area of the hydraulic system is considered a sequence of formation of mathematical models of flow distribution. The solution of the variational problem allows to obtain a system of equations describing the transient flow regime for the protection of objects of management tasks in safety performance.

scholarly journals Prediction Method of Cavitation Jet Wave Attenuation Based on Five-Equation Two-Fluid Model

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
You Fu ◽  
Zhaopeng Xie ◽  
Weiguo Zhao
Keyword(s):  
Calculation Method ◽  
Transient Flow ◽  
Wave Attenuation ◽  
Fluid Model ◽  
Flow Characteristics ◽  
Prediction Method ◽  
Friction Model ◽  
Velocity Flow ◽  
Numerical Calculation Method ◽  
Two Fluid

In this paper, the seven-equation two-fluid flow model is streamlined to a five-equation numerical calculation method. This method is applied to predict the wave attenuation of the cavitation jet. Compared with 9 different experimental schemes in two separate laboratories, it is found that the velocity flow characteristics are different from normal transient flow when the cavitation jet is formed in the pipeline. Such a difference in velocity flow characteristics will cause changes in the prediction deviation of pressure response time and amplitude. A numerical method for predicting the attenuation of pressure fluctuation with the cavitation jet is presented taken into account these flow characteristics. In this method, the unsteady friction model is opened after the jet wave transmits 3–5 cycles, and the cavitation jet wave attenuation is well simulated. This calculation method could provide a research basis for pipeline leakage, vibration, noise, and other fields that need accurate pressure signals.

Modeling the Characteristics of Thermally Governed Transient Flow Surges in Multitube Two-Phase Condensing Flow Systems With Compressibility and Thermal and Flow Distribution Asymmetry

1997 ◽  
Vol 119 (3) ◽  
pp. 534-543 ◽  
Author(s):  
G. L. Wedekind ◽  
C. J. Kobus ◽  
B. L Bhatt
Keyword(s):  
Flow Rate ◽  
Transient Flow ◽  
Flow Distribution ◽  
Vapor Flow ◽  
Complex Flow ◽  
Two Phase ◽  
Physical Mechanisms ◽  
Tube Type ◽  
Design Perspective ◽  
Spreadsheet Software

In a tube-type condenser involving complete condensation, small changes in the inlet vapor flow rate momentarily cause very large transient surges in the outlet mass flow rate. An Equivalent Single-Tube Model (ESTM), based on the System Mean Void Fraction Model, is developed that predicts these transient flow surges for a multitube system; including the effects of compressibility as well as thermal and flow distribution asymmetry. The model is verified theoretical and experimentally. From a design perspective, the significant value of the ESTM is that it includes the primary physical mechanisms involved in such complex flow transients, yet is simple enough to be solved on typical “spreadsheet” software.

High Speed Transient Flow in Manifolds

2019 ◽  
Author(s):  
Nicholas Findanis
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
High Speed ◽  
Transient Flow ◽  
Flow Distribution ◽  
Ideal Gas ◽  
Working Fluid ◽  
High Speed Flow ◽  
Speed Flow ◽  
High Speed Flows

Abstract Flows in manifolds is a ubiquitous and important area to implement flow improvements. In almost all applications of industrial pipe flows, there is the requirement to distribute the flow of fluid. There is a deficiency of studies in the area of flow distribution in manifolds with high speed flows. The present work is aimed at providing a further understanding of transient high speed flow distribution in manifolds. The different manifold configurations were analysed computationally. A comparison was focused between through the different aspect ratio manifolds. The velocity field and the eddy viscosity parameters where compared between the simulated flow models to ascertain the key features in the distributed flow field and especially, to determine the areas that showed greater flow recirculation or flow eddies and the separated flow regions. The CFD study was conducted as a high speed flow/ compressible flow regime accounting for the ideal gas dynamic model being air as the working fluid. The study showed that the transient behaviour of flow field can significantly affect distribution of the flow depending on the aspect ratio and number of branches on the manifold. Efficiency gains can be achieved in high speed flows that can be of benefit in industrial and other engineered flow applications.

Study on Calculation Method of Cooling Oil Flow Rate Allocation for Natural Oil Circulation Transformer

2017 ◽  
Author(s):  
Rong Xie ◽  
Na Wang ◽  
Zifu Lu ◽  
Zhonglin Cheng ◽  
Baopeng Xu
Keyword(s):  
Porous Media ◽  
Calculation Method ◽  
Low Voltage ◽  
Power Transformer ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Porous Media Model ◽  
Oil Flow ◽  
Calculation Results ◽  
Natural Oil

For the natural oil circulation power transformer, the hot spot temperature and winding temperature should be within prescribed limits so as to ensure its life and reliability. Temperature rise of inner windings not only depends on the transformer loss, but relates to oil flow closely. Therefore, whether the oil flow of transformer and oil flow distribution rules among the three windings can be predicted or not, relates to success or failure of the winding temperature rise research. According to the structural characteristics of transformer, a three-dimensional computational model including windings and external radiators was built by a three-dimensional modeling software. Initially, from the view of flow, the flow resistance of natural oil circulation power transformer windings has been calculated and analyzed using the CFD methodology, and the resistance characteristic curves about high voltage windings, middle voltage windings, low voltage windings, radiators and pipelines were fitted respectively by the least square method. And then, on the basis of above, the porous media model was applied to simplify the integral model of transformer so as to build a three-dimensional coupled porous media-pure fluid computational model. Meanwhile, the author calculated porosities and linear resistance coefficients of high voltage, middle voltage and low voltage windings. At the end of this paper, to obtain the relationship of oil flow distribution among three windings, the pressure loss was calculated by numerical simulation. Compared with the theoretical calculation results which was based on the part of experimental data, the numerical calculation results are in agreement with these data. And the error between them is within 6 percent. Therefore, the feasibility and accuracy of calculation method, which was used to calculate oil flow of natural oil circulation power transformer windings by the porous media model, has been verified as well. There are two kinds of conventional method to calculate oil flow, including an empirical method and an experimental method. On the one hand, although the former kind of method can be applied conveniently, it cannot consider all the factors so that the accuracy cannot be guaranteed. On the other hand, experimental method to calculate the flow can present high accuracy, but the cost of carrying out experimental study is high. Therefore, this paper presents another calculation method aimed to the flow resistance and oil flow by CFD. And the calculation method presented has higher calculation accuracy compared to above. Meanwhile, the new method provides a theoretical reference about oil flow distribution for the design of the power transformer.

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