SOFC Modeling at the Cell Scale Including Hydrogen and Carbon Monoxide as Electrochemically Active Fuels

2012 ◽  
Author(s):  
Martin Andersson ◽  
Maria Navasa ◽  
Jinliang Yuan ◽  
Bengt Sundén
Keyword(s):  
Carbon Monoxide ◽  
Current Density ◽  
Two Dimensions ◽  
The Finite Element Method ◽  
Internal Reforming ◽  
Electrochemically Active ◽  
Electrode Interface ◽  
Computational Fluid Dynamics Cfd ◽  
Ion Current Density ◽  
Fully Coupled

Fuel cells are promising for future energy systems, because they are energy efficient and able to use renewable fuels. A fully coupled computational fluid dynamics (CFD) approach based on the finite element method (with the software COMSOL Multiphysics) in two-dimensions is developed to describe an intermediate temperature solid oxide fuel cell (SOFC) single cell. Governing equations covering heat, gas-phase species, momentum, ion and electron transport are implemented and coupled to kinetics describing internal reforming and electrochemical reactions. Both hydrogen and carbon monoxide are considered as electrochemically active fuels within the anode. The activation polarization in the electrodes and the ohmic polarization due to ion transport in the YSZ material are found to be the major part of the potential losses. The activation polarization is the most significant and it is smaller within the cathode compared to the anode for this study. The ion current density and the activation polarization are the highest at the electrolyte-electrode interface and decrease rapidly within the electrodes as the distance from the interface increases. However, the ohmic polarization by ion transfer increases for the positions away from the interface. The addition of the electrochemical reaction with CO as fuel increases the current density. It is concluded that the temperature and current density are strongly integrated and when any of them is changed, the other follows, and the change is accelerated.

scholarly journals Numerical investigation of the effects of unsupported railway sleepers on train-induced environmental vibrations

2017 ◽  
Vol 36 (2) ◽  
pp. 160-176 ◽  
Author(s):  
Seyed-Ali Mosayebi ◽  
Morteza Esmaeili ◽  
Jabbar-Ali Zakeri
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Two Dimensions ◽  
Railway Track ◽  
Sensitivity Analyses ◽  
Regression Equations ◽  
The Finite Element Method ◽  
Technical Literature ◽  
Support Force ◽  
Comparison Of The Results

Review of technical literature regarding to train-induced vibrations shows that the effects of unsupported railway sleepers on this issue have been less investigated. So, the present study was devoted to numerical investigations of the mentioned issue. In this regard, first the problem of longitudinal train–track dynamic interaction was simulated in two dimensions by using the finite element method and the developed model was validated through comparison of the results with those obtained by previous researchers. In the next stage, a series of sensitivity analyses were accomplished to account for the effects of value of gap beneath the unsupported sleeper(s) and the track support stiffness on increasing the sleeper displacement and track support force. Moreover, the raised sleeper support force was introduced as applied load to a two-dimensional plane strain finite element model of track in lateral section and consequently the train-induced vibrations were assessed. As a result, a series of regression equations were established between the peak particle velocity in the surrounding environment of railway track and the sleeper support stiffness for tracks without unsupported sleepers and with one and two unsupported sleepers.

Radiation-induced change of polyimide properties under high-fluence and high ion current density implantation

2004 ◽  
Vol 78 (7) ◽  
pp. 1067-1072 ◽  
Author(s):  
V.N. Popok ◽  
I.I. Azarko ◽  
R.I. Khaibullin ◽  
A.L. Stepanov ◽  
V. Hnatowicz ◽  
...  
Keyword(s):  
Current Density ◽  
Ion Current ◽  
High Fluence ◽  
Radiation Induced ◽  
Ion Current Density

CO2 electrolysis to multicarbon products in strong acid

Science ◽  
2021 ◽  
Vol 372 (6546) ◽  
pp. 1074-1078
Author(s):  
Jianan Erick Huang ◽  
Fengwang Li ◽  
Adnan Ozden ◽  
Armin Sedighian Rasouli ◽  
F. Pelayo García de Arquer ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Carbon Emissions ◽  
Active Sites ◽  
Cell Voltage ◽  
Strong Acid ◽  
Electrochemically Active ◽  
Co2 Electrolysis ◽  
A Current

Carbon dioxide electroreduction (CO2R) is being actively studied as a promising route to convert carbon emissions to valuable chemicals and fuels. However, the fraction of input CO2 that is productively reduced has typically been very low, <2% for multicarbon products; the balance reacts with hydroxide to form carbonate in both alkaline and neutral reactors. Acidic electrolytes would overcome this limitation, but hydrogen evolution has hitherto dominated under those conditions. We report that concentrating potassium cations in the vicinity of electrochemically active sites accelerates CO2 activation to enable efficient CO2R in acid. We achieve CO2R on copper at pH <1 with a single-pass CO2 utilization of 77%, including a conversion efficiency of 50% toward multicarbon products (ethylene, ethanol, and 1-propanol) at a current density of 1.2 amperes per square centimeter and a full-cell voltage of 4.2 volts.

scholarly journals Far-Field Plume Characterization of a 100-W Class Hall Thruster

Aerospace ◽  
2020 ◽  
Vol 7 (5) ◽  
pp. 58
Author(s):  
Thibault Hallouin ◽  
Stéphane Mazouffre
Keyword(s):  
Energy Distribution ◽  
Current Density ◽  
Low Voltage ◽  
Ion Current ◽  
Hall Thruster ◽  
Far Field ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
The Core ◽  
Ion Current Density

The 100 W-class ISCT100-v2 Hall Thruster (HT) has been characterized in terms of far-field plume properties. By means of a Faraday Cup and a Retarding Potential Analyzer, both the ion current density and the ion energy distribution function have been measured over a 180 ∘ circular arc for different operating points. Measurements are compared to far-field plume characterizations performed with higher power Hall thrusters. The ion current density profiles remain unchanged whatever the HT input power, although an asymptotic limit is observed in the core of the plume at high discharge voltages and anode mass flow rates. In like manner, the ion energy distribution functions reveal that most of the beam energy is concentrated in the core of the plume [ − 40 ∘ ; 40 ∘ ] . Moreover, the fraction of low energy ion populations increases at large angles, owing to charge exchange and elastic collisions. Distinct plume regions are identified; they remain similar to the one described for high-power HTs. An efficiency analysis is also performed in terms of current utilization, mass utilization, and voltage utilization. The anode efficiency appears to be essentially affected by a low voltage utilization, the latter originating from the large surface-to-volume ratio inherent to low-power HTs. Experimental results also show that the background pressure clearly affects the plume structure and content.

Impact Factors in Measurements of Ion-Current Density Produced by High-Voltage DC Wire's Corona

2013 ◽  
Vol 28 (3) ◽  
pp. 1414-1422 ◽  
Author(s):  
Chao Fang ◽  
Xiang Cui ◽  
Xiangxian Zhou ◽  
Tiebing Lu ◽  
Yongzan Zhen ◽  
...  
Keyword(s):  
High Voltage ◽  
Current Density ◽  
Ion Current ◽  
Impact Factors ◽  
Ion Current Density

Developing an Advance Tire Hydroplaning Model Using Co-Simulation of Fully Coupled FEM and CFD Codes to Estimate Cornering Force

2018 ◽  
Author(s):  
Ashkan Nazari ◽  
Lu Chen ◽  
Francine Battaglia ◽  
Saied Taheri
Keyword(s):  
Cfd Model ◽  
Fluid Structure Interactions ◽  
Two Phase ◽  
Fluid Structure ◽  
The Public ◽  
Element Size ◽  
Road Surfaces ◽  
Computational Fluid Dynamics Cfd ◽  
Fully Coupled ◽  
Surrounding Fluid

Hydroplaning is a phenomenon which occurs when a layer of water between the tire contact patch and pavement pushes the tire upward. The tire detaches from the pavement, preventing it from providing sufficient forces and moments for the vehicle to respond to driver’s control inputs such as breaking, acceleration and steering. This work is mainly focused on the tire and its interaction with the pavement to address hydroplaning. Fluid Structure Interactions (FSI) between the tire-water-road surfaces are investigated through two approaches. In the first approach, the coupled Eulerian-Lagrangian (CEL) formulation was used. The drawback associated with the CEL method is the laminar assumption and that the behavior of the fluid at length scales smaller than the smallest element size is not captured. As a result, in the second approach, a new Computational Fluid Dynamics (CFD) Fluid Structure Interaction (FSI) model utilizing the shear-stress transport k-ω model and the two-phase flow of water and air, was developed that improves the predictions with real hydroplaning scenarios. Review of the public literature shows that although FEM and CFD computational platforms have been applied together to study tire hydroplaning, developing the tire-surrounding fluid flow CFD model using Star-CCM+ has not been done. This approach, which was developed during this research, is explained in details and the results of hydroplaning speed and cornering force from the FSI simulations are presented and validated using the data from literature.

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