Numerical simulation on macro-instability of coupling flow field structure in jet-stirred tank

Large eddy simulation (LES) was made to solve the flow around two simplified CRH2 high speed trains passing by each other at the same speed base on the finite volume method and dynamic layering mesh method and three dimensional incompressible Navier-Stokes equations. Wind tunnel experimental method of resting train with relative flowing air and dynamic mesh method of moving train were compared. The results of numerical simulation show that the flow field structure around train is completely different between wind tunnel experiment and factual running. Two opposite moving couple of point source and point sink constitute the whole flow field structure during the high speed trains passing by each other. All of streamlines originate from point source (nose) and finish with the closer point sink (tail). The flow field structure around train is similar with different vehicle speed.

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Numerical Simulation of Fractal Tree-Shaped Flow Field Structures in PEMFC

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.151.32 ◽

2012 ◽

Vol 151 ◽

pp. 32-35 ◽

Cited By ~ 2

Author(s):

Jin Hua Dong ◽

Shun Fang Liu

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Mass Transfer ◽

Flow Field ◽

Proton Exchange Membrane ◽

Plant Root ◽

Fractal Theory ◽

Bipolar Plate ◽

Field Structure ◽

Proton Exchange

The fractal tree-shaped structure such as tree, plant root, leaves, animal lung and so on is universal and unique in nature. These structures possess the symmetric micro-channel distributions and the efficient transport characteristics. They are considered to be an optimal network channel of mass transfer and heat transfer. The mass transfer and heat transfer feature of bipolar plate in proton exchange membrane fuel cell (PEMFC) is similar with animal lungs and leaves. In this paper, fractal theory is used to study tree-shaped flow field structure of bipolar plate in PEMFC. It is demonstrated by numerical simulation that fractal tree-shaped flow field structure can provide substantially flow-field distribution, current density and heat transfer compared to the traditional flow field structure.

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Numerical Simulation of Bottomhole Flow Field Structure in Particle Impact Drilling

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/108/3/032080 ◽

2018 ◽

Vol 108 ◽

pp. 032080

Author(s):

Weidong Zhou ◽

Jinsong Huang ◽

Luopeng Li

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Field Structure ◽

Particle Impact

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.732-733.432 ◽

2013 ◽

Vol 732-733 ◽

pp. 432-435 ◽

Cited By ~ 1

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.

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Numerical Simulation of Internal Flow Field in Mixed Flow Fan

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.860-863.1589 ◽

2013 ◽

Vol 860-863 ◽

pp. 1589-1593

Author(s):

Yan Zhao Zhai ◽

Hong Ming Zhang

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Velocity Distribution ◽

Pressure Distribution ◽

Three Dimensional ◽

Internal Flow ◽

Field Structure ◽

Mixed Flow ◽

Flow Phenomenon ◽

Impeller Outlet

The numerical simulation of internal flow field of a mixed-flow fan was carried out on the star-CD platform. Three-dimensional steady turbulent flow is calculated using the standard k-ɛ turbulence model, and the pressure distribution, velocity distribution and other important flow phenomenon inside the fan are obtained. The number of meshes has important influence on the result, meanwhile, fan inlet, impeller, outlet interact with each other. The results of numerical simulation can accurately analyze the fan flow field. The results of numerical simulation can accurately analyze the fan flow field structure, and provide guidance for further optimization and improvement of the fan.

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Numerical Simulation on the Influence of Injection Location, Injection Angle, and Divergence Half Angle on SITVC Nozzle Flow Field

International Journal of Aerospace Engineering ◽

10.1155/2019/7392497 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 1

Author(s):

H. R. Noaman ◽

Hai Bin Tang ◽

Elsayed Khalil

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Field Structure ◽

Nozzle Flow ◽

Performance Parameters ◽

Injection Angle ◽

Side Force ◽

Wide Range ◽

Half Angle ◽

Injection Location

A numerical study has been performed to characterize the nozzle flow field of secondary injection thrust vector control (SITVC) and to estimate the performance parameters of SITVC. After validating the CFD turbulence models with an experimental data, a numerical simulation has been conducted in order to investigate the influence of changing the injection location, the injection angle, and the primary nozzle divergence half angle on the SITVC nozzle flow field structure and on the SITVC performance parameters. The secondary mass flow rate was kept constant for all cases during the simulation. The results showed that downstream injection near the nozzle exit Mp=2.75 increases the high-pressure zone upstream the injection leading to an increase in the side force; also, the higher divergence half angle 15° slightly increases the side force and it provides a wide range of deflection without shock impingement on the opposite wall becoming more effective for SITVC. The injection angle in the upstream direction 135° increases the side force, and by decreasing the injection angle to downstream direction 45°, the side force decreases. However, the SITVC performance parameters and the flow field structure are more influenced by the injection location and the primary nozzle divergence half angle while being less influenced by the injection angle.

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