scholarly journals The performance of flow field channel in direct methanol fuel cell

2021 ◽  
Vol 2070 (1) ◽  
pp. 012081
Author(s):  
P V Sachin ◽  
Asha Sathish ◽  
T S Boopathi

Abstract A 3D computational fluid dynamics (CFD) model is developed to examine the impact of flow field design on the performance of direct methanol fuel cells (DMFCs). Effect of three various type flow fields is investigated in this study: single, double serpentine and honeycomb models. The distribution of velocity and temperature are simulated in 3D models. According to simulation studies, the honeycomb flow field has made uniform flow velocity distribution and minimum temperature change on plate surface. This could result better on DMFC performance. The experimental studies emphasize the performance of a single cell DMFC with different flow field channel designs as well as exhibit maximum power density and open circuit voltage. In subsequent study, electrodeposited Ni-Co alloy on stainless steel mesh surface is utilized to oxidize methanol and the electrode performance has been tested using cyclic voltammetry in alkaline conditions to replace expensive and sensitive platinum and platinum alloy catalysts

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Andreas Krug ◽  
Peter Busse ◽  
Konrad Vogeler

An important aspect of the aerodynamic flow field in the tip region of axial compressor rotors is the unsteady interaction between the tip clearance vortex (TCV) and the incoming stator wakes. In order to gain an improved understanding of the mechanics involved, systematic studies need to be performed. As a first step toward the characterization of the dynamic effects caused by the relative movement of the blade rows, the impact of a stationary wake-induced inlet disturbance on a linear compressor cascade with tip clearance will be analyzed. The wakes were generated by a fixed grid of cylindrical bars with variable pitch being placed at discrete pitchwise positions. This paper focuses on experimental studies conducted at the newly designed low-speed cascade wind tunnel in Dresden. The general tunnel configuration and details on the specific cascade setup will be presented. Steady state flow field measurements were carried out using five-hole probe traverses up- and downstream of the cascade and accompanied by static wall pressure readings. 2D-particle image velocimetry (PIV) measurements complemented these results by visualizing the blade-to-blade flow field. Hence, the structure of the evolving secondary flow system is evaluated and compared for all tested configurations.


2018 ◽  
Vol 43 (2) ◽  
pp. 1152-1170 ◽  
Author(s):  
David Ouellette ◽  
Adnan Ozden ◽  
Mustafa Ercelik ◽  
C. Ozgur Colpan ◽  
Hadi Ganjehsarabi ◽  
...  

2006 ◽  
Vol 4 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Guo-Bin Jung ◽  
Ay Su ◽  
Cheng-Hsin Tu ◽  
Fang-Bor Weng ◽  
Shih-Hung Chan

The flow-field design of direct methanol fuel cells (DMFCs) is an important subject about DMFC performance. Flow fields play an important role in the ability to transport fuel and drive out the products (H2O,CO2). In general, most fuel cells utilize the same structure of flow field for both anode and cathode. The popular flow fields used for DMFCs are parallel and grid designs. Nevertheless, the characteristics of reactants and products are entirely different in anode and cathode of DMFCs. Therefore, the influences of flow fields design on cell performance were investigated based on the same logic with respect to the catalyst used for cathode and anode nonsymmetrically. To get a better and more stable performance of DMFCs, three flow fields (parallel, grid, and serpentine) utilized with different combinations were studied in this research. As a consequence, by using parallel flow field in the anode side and serpentine flow-field in the cathode, the highest power output was obtained.


Author(s):  
Masaki Fuchiwaki ◽  
Tomoki Kurinami ◽  
Kazuhiro Tanaka

There have been a number of studies on the flow field around a pitching airfoil and a heaving airfoil. Especially, the relationship between the wake structure and the characteristics of dynamic thrust has been clarified. Recently, the flow field around an elastic body has been attracted significant attention and the flow field is treated as a coupled problem between the fluid and structure. The flow field around an elastic body has been investigated primarily by numerical means, and there have been experimental studies. However, the details of the impact of elastic deformation effects on the growth process of vortices generated in the vicinity of the wall have not been clarified. In this study, we investigate the growth process of vortices generated in the vicinity of the wall of elastic moving airfoils experimentally. The elastic NACA0010 generates vortices in a large region of a wall and rolls up vortices, with the vortices growing gradually toward the trailing edge as a result of elastic deformation. The elastic NACA0010 has a characteristic whereby vortices having a rotational component that is stronger than the shear-strain component due to the vorticities in the vicinity of a wall of the elastic NACA0010 change not only spatial change of x- and y-components.


2009 ◽  
Vol 60-61 ◽  
pp. 260-264
Author(s):  
Bo Zhang ◽  
Yu Feng Zhang ◽  
Xiao Wei Liu ◽  
Peng Zhang

Based on the visualization technology, we investigated experimentally the effect of different flow patterns on anode fluid behaviors of the μDMFC (Micro Direct Methanol Fuel Cell) with a transparent material under the same condition. Stainless steel mesh was utilized as the current collector which was distinct from the carbon cloth or carbon paper. Four dissimilar flow patterns were developed and tested. The observation of the effect of different flow patterns revealed that movements of dilute methanol solutions and CO2 gas bubbles in the dot and parallel flow fields represented more difficult, which could result in a decline of the μDMFC performance. The study also showed that a channel blocking in the single-serpentine flow field would be extremely terrible which could lead to a fuels leaking of the μDMFC, meanwhile the liquid-gas flow was more fluent and stable in a double-serpentine flow field. Therefore, due to its advantages, a double-serpentine flow pattern is more suitable for the μDMFC application compared with the other flow patterns.


Author(s):  
Guo-Bin Jung ◽  
Ay Su ◽  
Cheng-Hsin Tu ◽  
Fang-Bor Weng ◽  
Shih-Hung Chan

The flow-field design of Direct Methanol Fuel Cells (DMFCs) is an important subject about the DMFCs performance. Flow-fields play an important role on ability to transport fuel and drive out the products (H2O, CO2). In general, most of fuel cells utilize the same structure of flow-field for both anode and cathode. The popular flow-fields used for DMFCs are parallel and grid designs. Nevertheless, the characteristics of reactants and products are entirely different in anode and cathode of DMFCs. Therefore; the influences of the flow-fields designs on the cell performance were investigated due to the same logic for catalyst used for cathode and anode differently. To get the better and more stable performance of DMFC, three flow-fields (Parallel, Grid and Serpentine) are utilized with different combination were studied in this research. As a consequence, by using parallel flow-field in anode side and serpentine flow -field in cathode, the most and highest power output was obtained.


2014 ◽  
Vol 997 ◽  
pp. 396-400
Author(s):  
Yu Guang Fan ◽  
Ting Wei

The method of computational fluid dynamics (CFD) is used to three-dimensional numerical simulation for the fluid flow process of ammonium persulfate crystallizer. By using standard model, this paper respectively simulated the flow field within the crystallizer in the impeller installation height of 1.2 m while stirring speed is of 60 r/min, 100 r/min and 200 r/min; and simulated the impact of the flow field inside the crystallizer when the stirring speed of 100 r/min and impeller installation height respectively is of 0.7 m, 1.2 m and 1.7 m. That calculation results show that: the velocity gradient is mainly concentrated in the area of internal draft tube and paddle around. With the increase of impeller speed, the flow velocity of the fluid within the crystallizer corresponding increases; and the energy also gradually decreases from mixing impeller to the settlement zone with the loss of the installation height, and the kinetic energy in the bottom of the crystallizer is reduced. Considering the energy and crystallization effect, selection of mixing speed of 100 r/min or so and installation height of about 1.2 m is more appropriate.


2014 ◽  
Vol 11 (3) ◽  
Author(s):  
Chia-Chieh Shen ◽  
Guo-Bin Jung ◽  
Feng-Bor Weng ◽  
Chia-Chen Yeh ◽  
Chih-Hung Lee ◽  
...  

Increasing interest in utilizing direct methanol fuel cells for portable applications has prompted the need for understanding of their operating characteristics. Approximately 80% of a direct methanol fuel cell stack's volume and weight arise from the bipolar plates. The bipolar plates have grooved anode and cathode flow fields, and have a critical influence on the cell stack performance and stability. However, there is little published data regarding design expansion from single cell to stack, and literature regarding the fuel/oxidant distribution in each cell is especially scant. Hence, this topic is the subject of the present study, which reports the design of a complete direct methanol fuel cell consisting of five single cells including a graphite bipolar plate, as well as an innovative anode and cathode flow channel design. By observing variations in operating parameters, such as applied load and the flow of methanol solution and air, the impact of each parameter on the output performance and stability of the stack was investigated.


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