scholarly journals Numerical Investigation Of Thermodiffusion Effects On PEM Fuel Cell Performance

2021 ◽  
Author(s):  
Rihab. Jaralla
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Finite Thickness ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Fuel Cell Performance ◽  
Catalyst Layers ◽  
Diffusion Layers

A novel mathematical model for an entire proton exchange membrane fuel cell (PEMFC) is developed with its focus placed on the modeling and assessment of thermodiffusion effects that have been neglected in previous studies. Instead of treating catalyst layers as interfaces of nil thickness, the model presented here features a finite thickness employed for catalyst layers, allowing for a more realistic description of electrochemical reaction kinetics arising in the operational PEMFC. To account for the membrane swelling effect, the membrane water balance is modeled by coupling the diffusion of water, the pressure variation, and the electro-osmotic drag. The complete model consisting of the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEMFC are numerically solved using the finite element method implemented into a commercial CFD (Comsol 3.4) code. Various flow and transport phenomena in an operational PEMFC are simulated using the newly developed model. The resulting numerical simulations demonstrate that the thermodiffusion has a noticeable impact on the mass transfer for the oxygen. It is also revealed through a systematic parametric study that, as the porosity of gas diffusion layers and catalyst layers increase, the current density of an operational PEMFC may increase. Also, it is found that a PEM fuel cell can perform better with reasonable high operating pressure and temperature, as well as a supply of fully humidified gaseous reactants.

scholarly journals Numerical Investigation Of Thermodiffusion Effects On PEM Fuel Cell Performance

2021 ◽  
Author(s):  
Rihab. Jaralla
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Finite Thickness ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Fuel Cell Performance ◽  
Catalyst Layers ◽  
Diffusion Layers

A novel mathematical model for an entire proton exchange membrane fuel cell (PEMFC) is developed with its focus placed on the modeling and assessment of thermodiffusion effects that have been neglected in previous studies. Instead of treating catalyst layers as interfaces of nil thickness, the model presented here features a finite thickness employed for catalyst layers, allowing for a more realistic description of electrochemical reaction kinetics arising in the operational PEMFC. To account for the membrane swelling effect, the membrane water balance is modeled by coupling the diffusion of water, the pressure variation, and the electro-osmotic drag. The complete model consisting of the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEMFC are numerically solved using the finite element method implemented into a commercial CFD (Comsol 3.4) code. Various flow and transport phenomena in an operational PEMFC are simulated using the newly developed model. The resulting numerical simulations demonstrate that the thermodiffusion has a noticeable impact on the mass transfer for the oxygen. It is also revealed through a systematic parametric study that, as the porosity of gas diffusion layers and catalyst layers increase, the current density of an operational PEMFC may increase. Also, it is found that a PEM fuel cell can perform better with reasonable high operating pressure and temperature, as well as a supply of fully humidified gaseous reactants.

Numerical Simulation of Droplet Emergence and Growth From Gas Diffusion Layers (GDLs) in Proton Exchange Membrane (PEM) Fuel Cell Flow Channels

2018 ◽  
Author(s):  
Jingru Benner ◽  
Mehdi Mortazavi ◽  
Anthony D. Santamaria
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Gas Diffusion Layers ◽  
Diffusion Layers ◽  
Flow Channels ◽  
Exchange Membrane ◽  
Over Time

Liquid water management is critical for Proton Exchange Membrane (PEM) fuel cell operation, as excessive humidity can lead to flooding and cell performance degradation. Water is produced in the cathode catalyst layer during the electrochemical reaction. If reactant gas streams become saturated, liquid water forms and must travel through anode and cathode Gas Diffusion Layers (GDLs) to reach flow channels for removal. Understanding the dynamic behavior of the droplet is critical to improve water removal strategies for PEM fuel cells. In this study a 3D, transient, two-phase model based on the Volume of Fluid (VOF) method was developed to study a single droplet in the gas channel. The formation, growth, and breakup of the droplet is tracked numerically and analyzed. The pressure drop across the droplet is monitored over time and compared with theoretical analysis. The droplet size and shape change over time for two different pore sizes are compared. The impact of various gases including air, helium, and hydrogen on droplet dynamics is presented. The viscous force and pressure force on the droplet and the drag coefficient are calculated.

scholarly journals Proton exchange membrane (PEM) fuel cell parametric study via mathematical modeling and numerical simulation.

2021 ◽  
Author(s):  
Rihab Jaralla
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Cell Models ◽  
Air Velocity ◽  
Air Inlet ◽  
Exchange Membrane

In the proton exchange membrane (PEM) fuel cell study, numerical analysis of complex and coupled multi-disciplinary processes involving the subjects of fluid dynamics, heat transfer, mass transport, and electrochemistry has been attempted over the past few decades. However, many resulting models are, in spite of fancier functionalities such as three-dimensionality, too complex to implement on account of the digital hardware requirement as well as computation time consumption. On the other hand, three-dimensional analytical models reported in literature look much simple, but they are embedded by a number of fairly unrealistic assumptions and, hence, lead to significantly weakened usability. In this thesis, a set of detailed two-dimensional non-isothermal computational models for PEM fuel cells in x-y and y-z planes are developed, which aims at the equivalency with the 3D PEM fuel cell model and, moreover, gains more insights with significantly reduced computational cost. The complete model consisting of the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEM fuel cell are numerically solved using the finite element method implemented into a commercial CFD (COMSOL) code. A comprehensive comparison with the experimental data has been performed to validate the 2D models developed in this study. On the basis of simulations of various flow and transport phenomena in an operational PEMFC, a systematic parametric study is conducted using the present developed PEM fuel cell models. A number of operating and design parameters are examined, including the operating pressure, ambient temperature, relative humidity, the porosity of the gas diffusion layer (GDL), the effective porosity of catalyst layer (CL), the porosity of membrane (M), the proton conductivity and the air inlet velocity at cathode side. The obtained results of this study revelaed that the membrane porosity, and air inlet velocity have considerable effects on the water content in the membrane, thus it is essential to select the proper values of these parameters to improve water management in the cell and avoid dehydration the membrane or flooding the electrode. Also, it is found that increasing air velocity at the inlet of the cathode gas channel has a significant effect on the temperature distribution in PEM fuel cell, as the temperature a noticeably dropped with higher inlet air velocity. The numerically results also found that with higher porosities of gas diffusion layers (GDLs) and catalyst layers (CLs), the performance of PEM fuel cell improved. In addition, it found that a higher performance can be achieved when fuel cell operated with reasonably higher operating temperature, operating pressure, proton conductivity and ensuring a full hydration of the reactants. The outcome of this study demonstrates that the present developed PEM fuel cell models can serve as a useful tool for understanding of transport and electrochemical phenomena in PEM fuel cell as well as for optimization of cell design and operating conditions.

IMPACT OF PRESSURE ON THE PERFORMANCE OF PROTON EXCHANGE MEMBRANE FUEL CELL

2017 ◽  
Vol 13 (9) ◽  
pp. 6462-6467 ◽  
Author(s):  
Muthukumar. M ◽  
Karthikeyan. P ◽  
Mathews Eldho ◽  
Nagarathinam. P ◽  
Panneer Selvam.E.P ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Peak Power ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Optimum Pressure ◽  
Fuel Cell Performance ◽  
Serpentine Flow Field ◽  
Exchange Membrane

The Proton Exchange Membrane (PEM) fuel cell performance not only depends on temperature but also depends on the operating pressure, which will increase the performance of the PEM fuel cell. The PEM fuel cell with serpentine flow field was modeled using Solidworks software and analyzed using ANSYS software. By analysis of three different pressures on the PEM fuel cell, and came to know that the optimum pressure gives the best performance. The peak power density occurs in the constant temperature of 323 K with the pressure of 2 bar.

In-Plane Temperature Measurement and Water Droplet Detection of a Proton Exchange Membrane Fuel Cell Using Phosphor Thermometry: Initial Development

2010 ◽  
Author(s):  
Kristopher Inman ◽  
Xia Wang ◽  
Brian Sangeorzan
Keyword(s):  
Fuel Cell ◽  
Water Droplet ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Cell Performance ◽  
Fuel Cell Performance ◽  
Phosphor Thermometry ◽  
Exchange Membrane

Thermal behavior inside fuel cells plays a significant role in fuel cell performance and durability. Internal temperatures of a proton exchange membrane (PEM) fuel cell govern the ionic conductivities of the polymer electrolyte, influence the reaction rate at the electrodes, and control the water vapor pressure inside the cell. Temperature gradients also influence mass transport due to phase-change-induced flow and thermo-osmosis. Many techniques developed for studying in situ temperatures such as thermocouples sensors either disrupt fuel cell performance or carry unknown accuracy. The objectives of this research are to design and construct thermal sensors based on the principles of the lifetime-decay method of phosphor thermometry to measure temperatures of cathode gas diffusion layer inside a PEM fuel cell with minimal invasion. The sensors also demonstrate the possibility of detecting water droplet formation in the flow channels qualitatively making it possible to experimentally relate local temperature distribution with liquid water formation. Further development is required in order to increase the accuracy and utility of the sensors before conclusive testing can be performed.

scholarly journals Proton exchange membrane (PEM) fuel cell parametric study via mathematical modeling and numerical simulation.

2021 ◽  
Author(s):  
Rihab Jaralla
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Cell Models ◽  
Air Velocity ◽  
Air Inlet ◽  
Exchange Membrane

In the proton exchange membrane (PEM) fuel cell study, numerical analysis of complex and coupled multi-disciplinary processes involving the subjects of fluid dynamics, heat transfer, mass transport, and electrochemistry has been attempted over the past few decades. However, many resulting models are, in spite of fancier functionalities such as three-dimensionality, too complex to implement on account of the digital hardware requirement as well as computation time consumption. On the other hand, three-dimensional analytical models reported in literature look much simple, but they are embedded by a number of fairly unrealistic assumptions and, hence, lead to significantly weakened usability. In this thesis, a set of detailed two-dimensional non-isothermal computational models for PEM fuel cells in x-y and y-z planes are developed, which aims at the equivalency with the 3D PEM fuel cell model and, moreover, gains more insights with significantly reduced computational cost. The complete model consisting of the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEM fuel cell are numerically solved using the finite element method implemented into a commercial CFD (COMSOL) code. A comprehensive comparison with the experimental data has been performed to validate the 2D models developed in this study. On the basis of simulations of various flow and transport phenomena in an operational PEMFC, a systematic parametric study is conducted using the present developed PEM fuel cell models. A number of operating and design parameters are examined, including the operating pressure, ambient temperature, relative humidity, the porosity of the gas diffusion layer (GDL), the effective porosity of catalyst layer (CL), the porosity of membrane (M), the proton conductivity and the air inlet velocity at cathode side. The obtained results of this study revelaed that the membrane porosity, and air inlet velocity have considerable effects on the water content in the membrane, thus it is essential to select the proper values of these parameters to improve water management in the cell and avoid dehydration the membrane or flooding the electrode. Also, it is found that increasing air velocity at the inlet of the cathode gas channel has a significant effect on the temperature distribution in PEM fuel cell, as the temperature a noticeably dropped with higher inlet air velocity. The numerically results also found that with higher porosities of gas diffusion layers (GDLs) and catalyst layers (CLs), the performance of PEM fuel cell improved. In addition, it found that a higher performance can be achieved when fuel cell operated with reasonably higher operating temperature, operating pressure, proton conductivity and ensuring a full hydration of the reactants. The outcome of this study demonstrates that the present developed PEM fuel cell models can serve as a useful tool for understanding of transport and electrochemical phenomena in PEM fuel cell as well as for optimization of cell design and operating conditions.

3-D Model of Proton Exchange Membrane Fuel Cells

2000 ◽  
Author(s):  
Tianhong Zhou ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Three Dimensional Model ◽  
Chemical Reaction Kinetics ◽  
Fuel Cell Performance ◽  
D Model

Abstract A comprehensive three-dimensional model for a proton exchanger membrane (PEM) fuel cell is developed to evaluate the effects of various design and operating parameters on fuel cell performance. The geometrical model includes two distinct flow channels separated by the membrane and electrode assembly (MEA). This model is developed by coupling the governing equations for reactant mass transport and chemical reaction kinetics. To facilitate the numerical solution, the full PEM fuel cell was divided into three coupled domains according to the flow characteristics. The 3-D model has been applied to study species transport, heat transfer, and current density distributions within a fuel cell. The predicated polarization behavior is shown to compare well with experimental data from the literature. The modeling results demonstrate good potential for this computational model to be used in operation simulation as well as design optimization.

Pore Structure Modeling of Flow in Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells

2010 ◽  
Author(s):  
Zhongying Shi ◽  
Xia Wang
Keyword(s):  
Fuel Cell ◽  
Pore Structure ◽  
Proton Exchange Membrane ◽  
Cell Model ◽  
Transport Phenomena ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Structure Model ◽  
Exchange Membrane

The gas diffusion layer (GDL) in a proton exchange membrane (PEM) fuel cell has a porous structure with anisotropic and non-homogenous properties. The objective of this research is to develop a PEM fuel cell model where transport phenomena in the GDL are simulated based on GDL’s pore structure. The GDL pore structure was obtained by using a scanning electron microscope (SEM). GDL’s cross-section view instead of surface view was scanned under the SEM. The SEM image was then processed using an image processing tool to obtain a two dimensional computational domain. This pore structure model was then coupled with an electrochemical model to predict the overall fuel cell performance. The transport phenomena in the GDL were simulated by solving the Navier-Stokes equation directly in the GDL pore structure. By comparing with the testing data, the fuel cell model predicted a reasonable fuel cell polarization curve. The pore structure model was further used to calculate the GDL permeability. The numerically predicted permeability was close to the value published in the literature. A future application of the current pore structure model is to predict GDL thermal and electric related properties.

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