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.

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.

Optimization of Groove-Hole Distribution with Equidistant and Unequal Diameter on Air-Cushion Belt Conveyor

2008 ◽  
Vol 44-46 ◽  
pp. 635-642
Author(s):  
J.F. Li ◽  
Suo Long Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Research And Development ◽  
Cross Section ◽  
Flow Model ◽  
Optimal Parameters ◽  
Belt Conveyor ◽  
Air Cushion ◽  
Fluent Software ◽  
Air Hole

In this paper, the research and development of the distribution of air-holes in the groove of air-cushion belt conveyor were introduced. The expressions of air-cushion pressure were given and the graph of it was shown as well. The air flow model nearby groove-holes and air outflow model on cross section were given too. In the same time, the distributing mode of equidistant air-holes with unequal diameter was studied and analyzed. In order to make up the shortage of the study on air-hole distributing mode of equidistant air-holes with unequal diameter on the air-cushion belt conveyor, an instance of the air-cushion flow field was numerically simulated based on the CFD software ,Fluent software. Several groups of data of different air-hole distributions, (for example, the center distances of air-holes in the groove of air-cushion belt conveyor are the same as each other and their diameters are different), were selected to compare with each other , and then, the results were compared with existing theory. According to the different results of the numerical simulation on the distributing mode of equidistant air-holes with unequal diameter, the optimal parameters of air-hole distributing mode were obtained, and the effect of prevent offset that comes the balance groove-hole on air-cushion belt conveyor. Moreover, the verification to prove the agreement between the results of numerically simulated and basic theory was carried out by the comparison analyses. The theoretical feasibility of air-hole distributing mode of equidistant air-holes with unequal diameter was analyzed.

Numerical Simulation Study on the Recovery Process of Autonomous Underwater Vehicle

2021 ◽  
Author(s):  
Weigang Huang ◽  
Donglei Zhang ◽  
Jiawei Yu ◽  
Tao He ◽  
Xianzhou Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Autonomous Underwater Vehicle ◽  
Flow Characteristics ◽  
Recovery Process ◽  
Underwater Vehicle ◽  
Hydrodynamic Performance ◽  
Time Step ◽  
Convergence Test ◽  
Motion Paths

Abstract AUV (Autonomous Underwater Vehicle) recovery is considerably influenced by the nearby flow field and simulations of AUV in different motion paths in the wake of a submarine with a propeller are presented in this paper. A commercial CFD solver STAR CCM+ has been used to research the motion and flow characteristics of AUV, which using the advanced computational continuum mechanics algorithms. The DARPA (Defense Advanced Research Projects Agency) SUBOFF Submarine (L1 = 4.356m) propelled with INSEAN (Italian Ship Model Basin) E1619 propeller is used in this study, and the self-propulsion characteristics of the propeller at an incoming flow velocity of 2.75m/s are obtained through numerical simulation and results are compared with the available experimental data to prove the accuracy of the chosen investigation methodology. A grid/time-step convergence test is performed for verification study. AUV (L2 = 0.4356m) is a smaller-scale SUBOFF without a sail, which approaches the submarine in different motion paths in the submarine wake at a relative speed combined with the dynamic overlapping grid technology. The hydrodynamic performance of the AUV when approaching the submarine and the velocity distribution of the surrounding flow field are analyzed, which provides a useful reference for underwater recovery of the AUV.

Research on Flow Characteristics of Aerostatic Circular Thrust Bearing with a Cone Cavity

2011 ◽  
Vol 308-310 ◽  
pp. 189-192
Author(s):  
Long Xing Chen ◽  
Wen Qi Ma ◽  
He Chun Yu ◽  
Hai Yan Liu ◽  
Hong Wang Du
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Thrust Bearing ◽  
Single Point ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Flow Passage ◽  
Testing Method ◽  
Measurement Results ◽  
Simulation And Experiment

The aerostatic circular thrust bearing was taken as a study subject. The numerical simulation method was used to calculate the flow passage. Meanwhile, the single-point testing method was used to test the pressure distribution. The simulation and experiment measurement results were compared and analyzed. The results show that: The single-point testing method is effective to capture the change of flow characteristics. The overall results of simulation and testing coincide with each other well. In the range of cone cavity, the flow pattern for the gas is turbulent flow, and the flow field should be divided into different zones for simulation.

Numerical Simulation of Atmospheric Flow Field around Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1379-1382
Author(s):  
Ying Jia ◽  
Li Zhang ◽  
Sheng Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Distribution ◽  
Cross Section ◽  
Horizontal Plane ◽  
Atmospheric Flow ◽  
Airflow Field ◽  
Distribution Laws ◽  
The Cross

This paper carries out a numerical simulation of the atmospheric flow field around bridge. The variation law of airflow field around bridge is studied. Velocity and pressure distribution laws of flow field in horizontal plane and the cross-section are discussed, and influence range of flow field around bridge area is identified.

Numerical Simulation of Turbulent Mixing for Dislocated Blades in a Stirred Tank

2011 ◽  
Vol 354-355 ◽  
pp. 559-563
Author(s):  
Lei Shi ◽  
Shen Jie Zhou ◽  
Feng Ling Yang ◽  
Fan Jin Hu
Keyword(s):  
Numerical Simulation ◽  
Turbulent Mixing ◽  
Stirred Tank ◽  
Industrial Processes ◽  
Mixing Efficiency ◽  
Mixing Process ◽  
Flow Number ◽  
Stirred Tanks ◽  
Calculation Results ◽  
Better Than

Mixing efficiency is an important parameter in the design of many industrial processes in stirred tanks. In this study, CFD technology was used to simulate the mixing process inside the stirred tank with dislocated blades and standard turbine. Calculations were performed to study the effects of agitator speed and the configuration of impellers on mixing efficiency. The results showed that the flow field in the stirred tank with the dislocated blades is better than the standard turbine, and the flow number of the dislocated blades had been improved while the power number had been reduced. According to calculation results of Wr, we found the mixing efficiency of the dislocated blades had been improved about 4 times than that of standard turbine.

scholarly journals Numerical Simulation of Full-Scale Three-Dimensional Fluid Flow in an Oscillating Reactor

2021 ◽  
Vol 9 ◽  
Author(s):  
Houjun Gong ◽  
Mengqi Wu
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Flow Field ◽  
Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Full Scale ◽  
Variation Patterns ◽  
Oscillating Motion ◽  
Resistance Coefficients

Marine reactors are subjected to additional motions due to ocean conditions. These additional motions will cause large fluctuation of flow rate and change the coolant flow field, making the system unstable. Therefore, in order to understand the effect of oscillating motion on the flow characteristics, a numerical simulation of fluid flow is carried out based on a full-scale three-dimensional oscillating marine reactor. In this study, the resistance coefficients of the lattice, rod buddle and steam generator are fitted, and the distribution of flow rate, velocity as well as pressure in different regions is investigated through the standard model. After additional oscillation is introduced, the flow field in an oscillating reactor is presented and the effect of oscillating angle and elevation on the flow rate is investigated. Results show that the oscillating motion can greatly change the flow field in the reactor; most of the coolant circulates in the downcommer and lower head with only a small amount of coolant entering the core; the flow fluctuation period is consistent with the oscillating period, and the flow variation patterns under different oscillating conditions are basically the same; since the flow amplitude is related to oscillating speed, the amplitude of flow rate rises when decreasing the maximum oscillating angle; the oscillating elevation has little effect on the flow rate.

Jet Flotation Column System Structure Design and Numerical Simulation of Two-Phase Flow

2012 ◽  
Vol 616-618 ◽  
pp. 655-661 ◽  
Author(s):  
Run Quan Yang ◽  
Huai Fa Wang ◽  
Jian Chao Liu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Model ◽  
Structure Design ◽  
System Structure ◽  
Two Phase ◽  
Air Bubble ◽  
Flotation Column ◽  
Column System ◽  
Simulation Results

A laboratory scale jet flotation column system was designed and air inflation for flotation column was provided by jet aerator with a chamber. In order to understand interior flow field distribution of jet aerator and flotation column, two-phase turbulent flow model was established by use of commercial computational fluid dynamics (CFD) software FLUENT 6.3.26. Modeling of the flow field was firstly established with GAMBIT 2.3.16; standard k-ε turbulence model and multiphase flow model MIXTURE were adopted for gas-liquid two-phase numerical simulation about jet aerator and flotation column. The simulation results show that gas-liquid two-phase mixing have been established by the cavity entrainment vortex flow in jet aerator with a chamber, and the distortion was really occurred although the reversed cone feed inlet have been designed, at the same time non-uniform distribution of air-bubble was also simulated. Simulation results can help to optimize the structure of the jet flotation column.

Modeling and Numerical Simulation of Flow Resistance Characteristics in Slowly-Varying Rectangular Cross-Section Microchannel

2016 ◽  
Author(s):  
Shen Teng ◽  
Wang Jiong ◽  
Sun Dong ◽  
Liu Yafeng ◽  
Tian Zhouyu
Keyword(s):  
Numerical Simulation ◽  
Theoretical Calculation ◽  
Cross Section ◽  
Flow Resistance ◽  
Rectangular Cross Section ◽  
Flow Characteristics ◽  
Aspect Ratios ◽  
Good Accord ◽  
Simulation Results ◽  
Poiseuille Number

In this paper, flow characteristics in slowly-varying rectangular microchannels with different aspect ratios and Re numbers ranging from 7 to 200 are investigated. The obtained simulation results are compared with theoretics values based on the Bernoulli equations. The results show that the simulation results just hold an average discrepancy of 10% with the theoretical calculation value whichis presents a good accord. All the research of microchannel, the Poiseuille number of the flow is inconstant within the range of Re number, except when the contract angle is small where Poiseuille number is essentially unchanged.

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