scholarly journals CFD simulation and investigation of a new radial flow field structure on the PEMFC circular bipolar plate

2021 ◽  
pp. ArticleID:211057
Author(s):  
Qizhen Xie ◽  
Keyword(s):  
Flow Field ◽  
Radial Flow ◽  
Cfd Simulation ◽  
Bipolar Plate ◽  
Field Structure

scholarly journals EFFECT OF GALLERIES ON THE WIND FLOW STRUCTURE AND POLLUTANT TRANSPORT WITHIN STREET CANYONS WITH OR WITHOUT FACADE ROUGHNESS ELEMENTS (BALCONIES)

2020 ◽  
Vol 7 (12) ◽  
pp. 45-59
Author(s):  
V. A. Karkoulias ◽  
P. E. Marazioti ◽  
D. P. Georgiou ◽  
E. A. Maraziotis
Keyword(s):  
Flow Field ◽  
Concentration Distribution ◽  
Cfd Simulation ◽  
Field Structure ◽  
Flow Structures ◽  
Street Canyons ◽  
Ansys Fluent ◽  
Roughness Elements ◽  
Computational Fluid Dynamics Cfd ◽  
The Vertical Distribution

This paper investigates how the structure of the flow field and the vertical distribution of the pollutant concentration near the wall facades of street canyons are affected by the presence of some elements such as street level galleries. Numerical results are presented for various gallery geometries in combination with facade roughness elements (balconies) for a canyon of an aspect ratio equal to h/w=2.33. The results were obtained by a Computational Fluid Dynamics (CFD) simulation employing the ANSYS-FLUENT suite that incorporated the k-e turbulent (RNG) model. The simulation generated several flow structures inside the canyon (mainly vortices), whose characteristic properties (e.g. number, strength and size) are discussed in terms of the effect of the galleries on the flow field structure and the roughness generated by the building façade balconies. The results indicate a significant influence on both the flow field structure and the mass concentration distribution of the polluting particles.

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

2012 ◽  
Vol 151 ◽  
pp. 32-35 ◽  
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.

scholarly journals CFD Simulation and Performance Investigation on a Novel Bionic Spider-Web-Type Flow Field for PEM Fuel Cells

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1526
Author(s):  
Qizhen Xie ◽  
Minggang Zheng
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Cfd Simulation ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Cathode Side ◽  
Spider Web ◽  
Polygonal Structure ◽  
Type Flow ◽  
The Impact

The products generated by the electrochemical reaction in the PEM fuel cell (PEMFC) are mainly concentrated in the flow field on the cathode side of the bipolar plate, and the oxygen introduced on the cathode has higher requirements to improve its diffusion performance by using the flow field structure. For this reason, the optimization of the cathode flow field of the PEMFC is essential. Inspired by the structure of a spider web, this paper proposes a novel spider-web-type flow field. In this kind of flow field, the shape of a polygonal structure and the number of layers of spiral flow channels are the two most crucial variables. In order to explore the impact of these two variables on the cathode flow field, complete three-dimensional PEMFC models with different values of the two variables were established, and the models were simulated by the method of CFD. By observing the results of oxygen distribution, the water removal performance and fuel cell output performance of different schemes, the optimal scheme of the polygonal structure and layer number are determined. Compared with the traditional flow field, it is proved that the optimization scheme is desirable in improving the performance of the cathode flow field in PEMFC.

Radial Flow Velocity Field for Predicting Upper-Bound Solutions for Plane Strain Extrusion

1968 ◽  
Vol 90 (1) ◽  
pp. 45-50
Author(s):  
R. G. Fenton
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Flow Velocity ◽  
Plane Strain ◽  
Upper Bound ◽  
Radial Flow ◽  
Flow Velocity Field ◽  
Wide Range ◽  
Ram Pressure ◽  
Considerable Range

The upper bound of the average ram pressure, based on an assumed radial flow velocity field, is derived for plane strain extrusion. Ram pressures are calculated for a complete range of reduction ratios and die angles, considering a wide range of frictional conditions. Results are compared with upper-bound ram pressures obtained by considering velocity fields other than the radial flow field, and it is shown that for a considerable range of reduction ratios and die angles, the radial flow field yields better upper bounds for the average ram pressure.

Influence of Flow-Field Structure on Uranium Isotope Separation in the Separation Nozzle

1978 ◽  
Vol 40 (3) ◽  
pp. 329-340 ◽  
Author(s):  
W. Berkhahn ◽  
W. Ehrfeld ◽  
G. Krieg
Keyword(s):  
Flow Field ◽  
Isotope Separation ◽  
Field Structure ◽  
Uranium Isotope

Numerical Simulation of Flowfield around High Speed Trains Passing by each other at the same Speed

2011 ◽  
Vol 97-98 ◽  
pp. 698-701
Author(s):  
Ming Lu Zhang ◽  
Yi Ren Yang ◽  
Li Lu ◽  
Chen Guang Fan
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flow Field ◽  
Point Source ◽  
High Speed ◽  
Stokes Equations ◽  
Field Structure ◽  
Vehicle Speed ◽  
Mesh Method ◽  
High Speed Trains

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.

Investigation on flow field structure and aerodynamic load in vacuum tube transportation system

2021 ◽  
Vol 215 ◽  
pp. 104681
Author(s):  
Sha Zhong ◽  
Bosen Qian ◽  
Mingzhi Yang ◽  
Fan Wu ◽  
Tiantian Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Transportation System ◽  
Field Structure ◽  
Aerodynamic Load ◽  
Vacuum Tube
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