Improvement of Performance on Flow-Cutoff of Flap Valves Set in the Pressurized Tank of Pumping Station Based on Numerical Simulation

2013 ◽  
Vol 419 ◽  
pp. 86-90
Author(s):  
Yong Hai Yu ◽  
Bin Cheng
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Large Scale ◽  
Axial Flow ◽  
Free Water ◽  
Flow Distribution ◽  
Pumping Station ◽  
Simplec Algorithm ◽  
Distribution Uniformity ◽  
Free Plane

Two small flap valves arranged in parallel for each pump were used as flow-cutoff device in certain large-scale axial flow pumping station where the pressurized tank was designed as outlet structure. The flap valves of side-set pump had the poorest performance on flow-cutoff in the pumping station. The flow field in the pressurized tank was shown based on numerical simulation in order to improve the flow-cutoff performance of flap valves. The standard k-ε turbulence model and momentum equations were solved in the SIMPLEC algorithm with the assumption that the free water surface remained flat as a stress-free plane of symmetry. The velocity distribution and free outflow were prescribed on inlet and outlet boundary respectively. Numerical simulation on the flow field in pressurized tank was done at three typical moments chosen in the basis of the flow variation in the process of shutdown of flap valves. The reason that two flap valves of side-set pump could not close simultaneously and the late closing flap valve had a huge force on the wall was analyzed based on the comparison of flow field for side-set pump and middle-set pump. The result from numerical simulation proves that the division pier with appropriate size which helps to improve the flow distribution uniformity is valid for the two flap valves of side-set pump to close simultaneously.

Numerical Simulation of Optimized Forebay of Pumping Station

2009 ◽  
Author(s):  
Li Cheng ◽  
Jiren Zhou
Keyword(s):  
Numerical Simulation ◽  
Large Scale ◽  
Experiment Data ◽  
Pumping Station ◽  
Calculation Results ◽  
Simplec Algorithm ◽  
Original Scheme ◽  
Volume Method ◽  
Calculated Model ◽  
Good Agreement

The incompressible N-S equations are solved by the finite volume method. Based on the standard k-e model, the SIMPLEC algorithm is applied for the solution of the discretization governing equation. Using CFD, the flow pattern in the forebay of pumping station is revealed. The calculation results showed that there were large scale recirculation in the forebay of original scheme and the flow patterns of optimized forebay with bottom sills were improved. The calculated results were in good agreement with experiment data, which show that the calculated model was reliable and practical.

Numerical Simulation of the Flow Field for Rotor Ventilation System of Large-Scale Nuclear Power Turbo-Generator

2012 ◽  
Vol 152-154 ◽  
pp. 1498-1504 ◽  
Author(s):  
Xiao Hu Zhang ◽  
Lei Hu ◽  
Jian Hua Yuan ◽  
Yi Chao Yuan
Keyword(s):  
Flow Field ◽  
Nuclear Power ◽  
Large Scale ◽  
Ventilation System ◽  
Flow Distribution ◽  
Basic Unit ◽  
Turbo Generator ◽  
Key Issues ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance

The nuclear power turbo-generator with large capacity is a basic unit of nuclear power plant, while the cooling technology becomes one of the key issues which affect its design and operation deeply. Axial-radial ventilation structure for rotor is commonly used in large nuclear power generator. In this article, according to the basic principles of computational fluid dynamics (CFD), ventilation’s structure and performance is analyzed, 3D flow model is also established. After the boundary conditions are determined, the numerical calculation and analysis is finished. And then, the rules of flow distribution is obtained, the flow field and the static pressure character of the gap is also computed, which could be very important to the ventilation system of the whole generator.

Numerical Simulation of the Temperature Field and the Flow Field Inside the Domestic Cooling and Heating Unit’s Water Tank

2012 ◽  
Author(s):  
Chao Zhu ◽  
Mo Yang ◽  
Yuwen Zhang ◽  
Jinlong Wang
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Flow Field ◽  
Water Temperature ◽  
Waste Heat ◽  
Flow Distribution ◽  
Water Tank ◽  
Heating Unit ◽  
Speed Up

A water tank of the domestic cooling and heating unit, which has a helix coil, is used to recover the waste heat of the unit. The temperature field and the flow field in the water tank have great effects on the variation of the water temperature in it. In order to obtain the temperature distribution, the flow distribution and the influencing factors, and then obtain the changing situation of the water temperature, the temperature field and the flow field of the water tank are simulated by using Fluent. The results showed that the water temperature will change with different coil decorate. The numerical model which is created by Fluent is appropriate and could be used to improve the layout of the coil in the water tank and speed up heating.

scholarly journals A study of the flow-field evolution and mixing in a planar turbulent jet using direct numerical simulation

2002 ◽  
Vol 450 ◽  
pp. 377-407 ◽  
Author(s):  
S. A. STANLEY ◽  
S. SARKAR ◽  
J. P. MELLADO
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Direct Numerical Simulation ◽  
Large Scale ◽  
Computational Study ◽  
Practical Interest ◽  
Small Scale ◽  
Mixing Process ◽  
Mean Velocity ◽  
Small Scales

Turbulent plane jets are prototypical free shear flows of practical interest in propulsion, combustion and environmental flows. While considerable experimental research has been performed on planar jets, very few computational studies exist. To the authors' knowledge, this is the first computational study of spatially evolving three-dimensional planar turbulent jets utilizing direct numerical simulation. Jet growth rates as well as the mean velocity, mean scalar and Reynolds stress profiles compare well with experimental data. Coherency spectra, vorticity visualization and autospectra are obtained to identify inferred structures. The development of the initial shear layer instability, as well as the evolution into the jet column mode downstream is captured well.The large- and small-scale anisotropies in the jet are discussed in detail. It is shown that, while the large scales in the flow field adjust slowly to variations in the local mean velocity gradients, the small scales adjust rapidly. Near the centreline of the jet, the small scales of turbulence are more isotropic. The mixing process is studied through analysis of the probability density functions of a passive scalar. Immediately after the rollup of vortical structures in the shear layers, the mixing process is dominated by large-scale engulfing of fluid. However, small-scale mixing dominates further downstream in the turbulent core of the self-similar region of the jet and a change from non-marching to marching PDFs is observed. Near the jet edges, the effects of large-scale engulfing of coflow fluid continue to influence the PDFs and non-marching type behaviour is observed.

scholarly journals Numerical simulation of hydraulic optimization for regulating tank in pumping station

2021 ◽  
Vol 880 (1) ◽  
pp. 012020
Author(s):  
Xiaoming Zhu ◽  
Sha Shi ◽  
Jing Si ◽  
Arniza Fitri ◽  
Dian Pratiwi ◽  
...  
Keyword(s):  
Flow Field ◽  
Side Wall ◽  
Engineering Practice ◽  
Governing Equations ◽  
Safe Operation ◽  
Pumping Station ◽  
Simplec Algorithm ◽  
Rng Turbulence Model ◽  
Wall Spacing ◽  
Good Agreement

Abstract Based on the governing equations of steady incompressible fluid, renormalization group (RNG) turbulence model and SIMPLEC algorithm are used to calculate the steady flow field of regulating tank in the pumping station with six different geometries operating under same condition. The impacts of the layout schemes of guide walls for the flow field of the regulating tank are analyzed. The numerical results are verified by physical model experiment and good agreement is found. The results show that: 1) serious flow separation of side wall will occur in the regulating tank when the interval of diversion wall is 10 L; 2) the flow velocity in the regulating tank will be too low when the diversion wall spacing is 16 L; 3) the improvement of the flow pattern of the regulating tank is not obvious; and the project cost is increased when the excavation depth of the regulating tank is increased by 1 m; 4) the bottom velocity reached the non-silting velocity and the head loss of the regulating tank reducing nearly 1.2 m by using arrangement form of wide 21 L and narrow 10L of the guide walls, which provides a certain guarantee for the safe operation of the pumping station. The regulation tank layout scheme proposed in the paper can be applied to engineering practice.

Numerical Simulation on the Performance of Vertical Jet Flowmeter of Natural Gas

2014 ◽  
Vol 598 ◽  
pp. 206-209
Author(s):  
Xiao Hua Wang ◽  
Zhe Xiao ◽  
Kai Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Linear Relationship ◽  
Pressure Fluctuation ◽  
Oscillation Frequency ◽  
Static Pressure ◽  
Vertical Drainage ◽  
Simplec Algorithm ◽  
Feedback Channels ◽  
Vertical Jet

In this paper, SimpleC algorithm and Realizable turbulence model are applied to simulate the detailed flow field of oscillator, which is the key component of the vertical drainage jet flowmeter. Based on analyzing the pressure fluctuation of fluid in the feedback channels of the oscillator at different flowrates, the results indicate that there is an obviously linear relationship between velocity and oscillation frequency of static pressure in the vertical feedback channels within a certain range of flowrate. The achievements can be helpful to the optimization the design of vertical drainage jet flowmeter.

FLOW FIELD AND TOPOLOGICAL ANALYSIS OF HEMISPHERICAL PARACHUTE IN LOW ANGLES OF ATTACK

2010 ◽  
Vol 24 (15) ◽  
pp. 1707-1725 ◽  
Author(s):  
YIHUA CAO ◽  
QIANFU SONG ◽  
ZHUO WU ◽  
JOHN SHERIDAN
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Flow Field ◽  
Topological Structure ◽  
Topological Analysis ◽  
Fluid Simulation ◽  
Navier Stokes ◽  
Structure Interaction ◽  
Simplec Algorithm ◽  
Stable Shape

For analyzing the flow field and topological structure of hemispherical parachute in low angles of attack, a fluid-structure interaction (FSI) simulation technique is established to decide the shape of the hemispherical parachute during terminal descent. In the fluid simulation, the semi-implicit method for pressure-linked equations consistent (SIMPLEC) algorithm is introduced to solve shear stress transport (SST) k–ω turbulence Navier–Stokes (N–S) Equations. This method is proved to be efficient and stable by the experiment and corresponding numerical simulation. After obtaining the stable shape of the canopy, the parachute in different angles and velocities are considered.

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