A 3D Single-Phase Numerical Model for a PEMFC Stack

2009 ◽  
Author(s):  
Anh Dinh Le ◽  
Biao Zhou
Keyword(s):  
Fluid Flow ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Single Phase ◽  
Single Cells ◽  
Three Dimensional ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Two Phase ◽  
Catalyst Layers

A single-phase, three-dimensional mathematical model has been constructed and implemented to simulate the fluid flow, heat transfer, species transport, electrochemical reaction, and current density distributions in a Proton Exchange Membrane Fuel Cell (PEMFC) stack with parallel-shaped channels. In this study, a complete PEMFC stack with 3 parallel single-cells including the membrane, gas diffusion layers (GDLs), catalyst layers, flow channels, and current collectors was taken into account. The reasonable numerical results show the detailed distributions of fluid flow and species concentrations in the channel and porous media, heat and current transports through the single cells in the stack. Furthermore, this successful modeling of a single-phase PEMFC stack would be a critical step to further develop a general two-phase PEMFC model that could investigate the water management and effects of liquid water on the performance of a fuel cell stack.

Investigation of Thermal Influence on the Assembly of Polymer Electrolyte Membrane Fuel Cell Stacks

2012 ◽  
Vol 512-515 ◽  
pp. 1509-1514
Author(s):  
Lin Fa Peng ◽  
Dian Kai Qiu ◽  
Pei Yun Yi ◽  
Xin Min Lai
Keyword(s):  
Thermal Expansion ◽  
Fuel Cell ◽  
Contact Pressure ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Fe Model ◽  
Assembly Process

The assembly force in a proton exchange membrane fuel cell (PEMFC) stack affects the characteristics of the porosity and electrical conductivity. Generally, the stack is assembled at room temperature while it’s operated at about 80 °Cor even higher. As a result, the assembly pressure can’t keep constant due to thermal expansion. This paper focuses on the contact pressure between membrane electrode assembly (MEA) and bipolar plates in real operations. A three-dimensional finite element (FE) model for the assembly process is established with coupled thermal-mechanical effects. The discipline of contact pressure under thermal-mechanical effect is investigated. A single cell stack is fabricated in house for the analysis of contact pressures on gas diffusion layer at different temperatures. The results show that as the temperature increases, contact pressure increases due to thermal expansion. It indicates that the influence of thermal expansion due to temperature variation should be taken into consideration for the design of the stack assembly process.

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.

A sharp interface reduction for multiphase transport in a porous fuel cell electrode

2006 ◽  
Vol 462 (2067) ◽  
pp. 789-816 ◽  
Author(s):  
Keith Promislow ◽  
John Stockie ◽  
Brian Wetton
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Moving Boundary ◽  
Relaxation Times ◽  
Phase Interface ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Parabolic Differential Equations ◽  
Two Phase ◽  
A Free Boundary Problem

The gas diffusion layer in the electrode of a proton exchange membrane fuel cell is a highly porous material which acts to distribute reactant gases uniformly to the active catalyst sites. We analyse the conservation laws governing the multiphase flow of liquid, gas and heat within the electrode. The model is comprised of five nonlinear-degenerate parabolic differential equations strongly coupled through liquid–gas phase change. We identify a scaling regime in which the model reduces to a free boundary problem for a moving two-phase interface. On each side of the moving boundary the nonlinear system is well approximated by its linearization whose relaxation times are much shorter than the front evolution. Using a quasi-steady reduction, we obtain an explicit leading-order evolution equation for the free surface in terms of the prescribed boundary conditions.

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.

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