Study of Flow Characteristics of Oil and Water in the Process of Stirring

2013 ◽  
Vol 353-356 ◽  
pp. 3190-3193
Author(s):  
Zong Rui Hao ◽  
Juan Xu ◽  
Hai Yan Bie ◽  
Zhong Hai Zhou
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Cross Section ◽  
Radial Flow ◽  
Flow Characteristics ◽  
Stirred Tank ◽  
Turbulent Model ◽  
Vof Model ◽  
Circular Flows ◽  
Oil Water

To study the flow pattern in the process of oil-water stirring in three paddle stirring tank, RNG k-ε turbulent model and VOF model are adopted to simulate the flow field at different time in the stirred tank with the baffle. The results showed that, in the stirring process, inverted cone manifold was formed in the center of the stirring shaft. The stratified area was formed in the baffle and gradually transported to the bottom of the tank. The two circular flows were formed among three groups of blades. And the axially acting of the fluid was strong, which made homogeneous stirring in the stirred tank. At the same time the radial flow of the cross-section inside the tank increased because of the baffle.

Numerical Simulation of the Effects of Baffle on Flow Field in a Stirred Tank

2013 ◽  
Vol 732-733 ◽  
pp. 432-435 ◽  
Author(s):  
Zong Rui Hao ◽  
Juan Xu ◽  
Hai Yan Bie ◽  
Zhong Hai Zhou
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Cross Section ◽  
Flow Model ◽  
Flow Characteristics ◽  
Stirred Tank ◽  
Stirred Tanks ◽  
Double Peak ◽  
Blade Area ◽  
Radial Circulation

Flow characteristics of stirred tanks with different structures were calculated by taking RNG k-ε model as the turbulent flow model. The results showed that at the same rotational speed, a large number of axial and radial vortexes were formed in the stirred tank with the baffle. The velocity in the blade area was high, and it decreased rapidly with the increasing distance to the blade. The double peak area of the radial velocity was formed in the stirred tank with baffle, and the high and low speed cycles were obtained in the cross-section. The baffle increased not only the axial circulation of the liquid in the tank but also the radial circulation, which help to mix the liquid.

Measuring Flow Pattern Asymmetry of Oil-Water Two Phase Flows Using Multi-channel Rotating Electric Field Conductance Signals

2018 ◽  
Vol 74 (1) ◽  
pp. 25-41 ◽  
Author(s):  
Yuansheng He ◽  
Yingyu Ren ◽  
Yunfeng Han ◽  
Ningde Jin
Keyword(s):  
Electric Field ◽  
Flow Pattern ◽  
Cross Section ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Time Asymmetry ◽  
Pipe Cross Section ◽  
Multi Scale ◽  
Oil Water

AbstractThe present study is a report on the asymmetry of dispersed oil phase in vertical upward oil-water two phase flow. The multi-channel signals of the rotating electric field conductance sensor with eight electrodes are collected in a 20-mm inner diameter pipe, and typical images of low pattern are captured using a high speed camera. With the multi-channel rotating electric field conductance signals collected at pipe cross section, multi-scale time asymmetry (MSA) and an algorithm of multi-scale first-order difference scatter plot are employed to uncover the fluid dynamics of oil-water two phase flow. The results indicate that MSA can characterise the non-linear behaviours of oil-water two phase flow. Besides, the MSA analysis also beneficial for understanding the underlying inhomogeneous distribution of the flow pattern in different directions at pipe cross section.

Investigation on Flow Characteristics of Deposited Water Displaced by Flowing Oil in Hilly Terrain Tube

2012 ◽  
Vol 516-517 ◽  
pp. 926-930
Author(s):  
Guang Li Xu
Keyword(s):  
Numerical Simulation ◽  
Test Section ◽  
Flow Characteristics ◽  
Geometrical Model ◽  
Water Interface ◽  
Two Dimensional ◽  
Hilly Terrain ◽  
Vof Model ◽  
Test Loop ◽  
Oil Water

The flow characteristics of deposited water displaced by flowing oil in hilly terrain tube were studied experimentally and numerically. Lab-scale experiments were carried out on the transparent organic glass test loop with I.D. 50 mm to investigate the distributions of oil-water interface by diesel flowing from a lower horizontal test section into the up-inclined test section. Two-dimensional numerical simulation was conducted by VOF model and CSF model based on the test geometrical model. Comparisons of the oil-water interface distribution and the critical superficial oil velocity show that the numerical simulations favorably compare with the measurements.

Francis-Type Reversible Turbine Field Investigation During Fast Closure of Wicket Gates

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Mao Xiuli ◽  
Pavesi Giorgio ◽  
Zheng Yuan
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Transient Flow ◽  
Flow Characteristics ◽  
Flow Simulation ◽  
Field Investigation ◽  
Electricity Demand ◽  
Field Analysis ◽  
Detached Eddy Simulation ◽  
Time Frequency

Flexible electricity demand and variability of the electricity produced by wind turbines and photovoltaic affect the stable operations of power grids. Pump-turbines are used to stabilize the power grid by maintaining a real-time electricity demand. Consistently, the machines experience transient conditions during the course of operation, such as start-up, load acceptance, load rejection, and shutdown, which induce high amplitude pressure pulsations and affect operating lifespan of the components. During the closure of the wicket gates, the transient flow characteristics is analyzed for a Francis-type reversible pump-turbine in generating mode by three-dimensional (3D) numerical simulation with a moving mesh technique and using detached eddy simulation (DES) turbulent model. Mesh motion is carried out in the region of wicket gates during the load rejection by a moving, sliding mesh, which makes dynamic flow simulation available, instead of building various steady models with different guide vanes angles. The transient flow characteristics are illustrated by analyzing the flow, torque, and pressure fluctuations signals by frequency and time–frequency analyses. The flow field analysis includes the onset and strengthening of unsteady phenomena during the turbine load reduction. The flow pattern in return channel maintained a quite stable flow field, whereas the flow pattern in the runner and draft tube emphasized its instability with the flow rate decreased. Influence of 3D unsteady flow structures on runner is determined, and its evolution is characterized spectrally during fast closure of wicket gates.

Units Commitment Optimization of Pumping Station Based on Velocity Uniformity Analysis

2013 ◽  
Vol 805-806 ◽  
pp. 1720-1723
Author(s):  
Xing Liang
Keyword(s):  
Experimental Data ◽  
Velocity Distribution ◽  
Flow Pattern ◽  
Unit Commitment ◽  
Flow Characteristics ◽  
Optimal Operation ◽  
Operation Strategy ◽  
Turbulent Model ◽  
Pumping Station ◽  
Better Than

The Realizable k-ε turbulent model is employed to simulate the flow pattern in forebay of pumping station, and the precision of simulated results is verified by experimental data. And then the flow pattern of the different unit commitments is simulated to acquire the flow characteristics in forebay, such as circulating flow and velocity distribution, and the velocity uniformity of forebay is analyzed to search the optimal units commitment. The research results show that: under the different unit commitment, the characteristics of flow in forebay is so different that the effect of the diversion piers is not always advantageous; comparing the velocity uniformity, the optimal operation strategy is to try to operate the middle pumps, and the operation strategy of operating pumps on both sides is better than that of opening pumps on one side.

Study on Flow Characteristics inside a Spillway Tunnel of Hydropower Station

2014 ◽  
Vol 716-717 ◽  
pp. 219-222
Author(s):  
Hong Qing Zhang ◽  
Bing Cao ◽  
Yi Long Lou ◽  
Wei Kai Tan
Keyword(s):  
Flow Velocity ◽  
High Speed ◽  
Flow Characteristic ◽  
Flow Characteristics ◽  
Hydropower Station ◽  
Turbulent Model ◽  
Cross Sectional ◽  
Vof Model ◽  
Spillway Tunnel ◽  
The Right

VOF model and turbulent model were used in this paper to study on flow characteristic inside a certain spillway tunnel of hydropower station, which includes cross sectional distributions of flow velocity in pressure section and non-pressure section. The results show that flow velocity distribution in the pressure section of the spillway tunnel is basically symmetrical. After turning, flow velocity is well-distributed and move ahead; flow velocity in the right side of non-pressure section in the spillway tunnel is 1m/s faster than that in the left side. When two high-speed water flow come together after passing through the central division pier, flow velocity distributions in the both sides of the spillway tunnel are all uniform. The conclusions obtained can improve the design of the spillway tunnel.

Numerical Simulation of Laminar Flow Field in a Stirred Tank with a Rushton Impeller or a Pitch 4-Bladed Turbine

2012 ◽  
Vol 557-559 ◽  
pp. 2375-2382
Author(s):  
Jun Ling Fan ◽  
De Yu Luan
Keyword(s):  
Laminar Flow ◽  
Flow Field ◽  
Equations Of Motion ◽  
Flow Characteristics ◽  
Stirred Tank ◽  
High Power Consumption ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Multiple Reference ◽  
Rushton Impeller

Computational fluid dynamics (CFD) method was applied to the study of flow field in the agitation of glycerin fluid with a Rushton impeller and a pitch 4-bladed turbine. The flow was modeled as laminar and a multiple reference frame (MRF) approach was used to solve the discretized equations of motion. The velocity profiles predicted by the simulation with four different impellers rotating at constant speed of 200r/min were obtained. By analysis to their axial, radial and tangent velocity vector plots, velocity contours and velocity distribution curves, it was found that the stirred effect of the Rushton impeller was better than one of the pitch 4-bladed turbines，however，accompanied with high power consumption according to the calculated values of required power. Moreover, there were all similar flow characteristics for the pitch 4-bladed turbines with different blade pitch angle. The research provided a theoretical basis for the design and practical application of the stirred tank under laminar flow.

CFD Study on the Flow Field and Power Characteristics in a Rushton Turbine Stirred Tank in Laminar Regime

2019 ◽  
Vol 17 (11) ◽  
Author(s):  
Li Liangchao ◽  
Chen Ning ◽  
Xiang Kefeng ◽  
Xiang Beiping
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Flow Pattern ◽  
Scale Up ◽  
Stirred Tank ◽  
Turbulent Regime ◽  
Laminar Regime ◽  
Power Number ◽  
Rushton Turbine ◽  
Working Medium

Abstract A computational fluid dynamics (CFD) simulation was performed to study the hydrodynamics characteristics in a Rushton turbine stirred tank in laminar regime. The effects of operating condition, working medium and geometrical parameter on the flow field and power number characteristics were investigated. It is found that the two-loop flow pattern is formed in laminar regime when the impeller is not very close to tank bottom, while its shape and size vary with Reynolds number and impeller diameter. For a given geometrical configuration, the flow pattern, power number and dimensionless velocity profile are mainly depended on Reynolds number, and do not change with working medium and scale-up for a constant Reynolds number. When impeller off-bottom clearance is too low and Reynolds number is relatively high, the fluid flow would transit from two-loop flow pattern to sing-loop flow pattern as that occurs in turbulent regime. Power number falls for larger impeller in laminar regime. Surprisingly, in laminar regime, power number in the baffled tank with small impeller is almost identical to that in the unbaffled tank.

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