Effect of Channel Geometry on Two-Phase Flow Structure in Fuel Cell Gas Channels

2011 ◽  
Author(s):  
Cody D. Rath ◽  
Satish G. Kandlikar
Keyword(s):  
Water Management ◽  
Fuel Cell ◽  
High Efficiency ◽  
Polymer Electrolyte Membrane ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Ex Situ ◽  
Two Phase ◽  
Electrolyte Membrane ◽  
Excess Water

Water management issues continue to be a major concern for the performance of polymer electrolyte membrane (PEM) fuel cells. Maintaining the optimal amount of hydration can ensure that the cell is operating properly and with high efficiency. There are several components that can affect water management, however one area that has received increased attention is the interface between the gas diffusion layer (GDL) and the gas reactant channels where excess water has a tendency to build up and block reactant gasses. One key parameter that can affect this build up is the geometry of the microchannels. The work presented here proposes an optimal trapezoidal geometry which will aid in the removal of excess water in the gas channels. The Concus-Finn condition is applied to the channel surfaces and GDL to ensure the water will be drawn away from GDL surface and wicked to the top corner of the channel. An ex situ setup is designed to establish the validity of the Concus-Finn application. Once validated, this condition is then used to design optimal channel geometries for water removal in a PEM fuel cell gas channel.

CFD Simulation of Flow Through the Reconstructed Microstructure of Fibrous Gas Diffusion Layer in a Polymer Electrolyte Membrane Fuel Cell

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Venkata Suresh Patnaikuni ◽  
Sreenivas Jayanti
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Diffusion Layer ◽  
Polymer Electrolyte Membrane ◽  
Effective Diffusion ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Electrolyte Membrane

AbstractThe gas diffusion layer (GDL) is one of the key components in a polymer electrolyte membrane (PEM) fuel cell. Generally it is a carbon-based fibrous medium that allows for the transport of electrons through the fibers and distributes the reactants through the void space to the catalyst layer in a PEM fuel cell. In the present work, a microstructure study of reactant transport is carried out by reconstructing the typical fibrous microstructure of the GDL and investigating the transport characteristics of the porous medium using computational fluid dynamics (CFD) simulations. The results confirm the applicability of Darcy’s law formulation for permeability determination and Bruggemann correction for calculation of effective diffusivity for typical conditions encountered in PEM fuel cells. Macroscopic material properties such as through-plane and in-plane permeabilities and effective diffusion coefficient are determined and compared against experimental values reported in the literature.

Water Management in PEMFC Stack of Fuel Cell Vehicle

2009 ◽  
Author(s):  
Sungho Lee ◽  
Heeseok Jeong ◽  
Inchul Whang ◽  
Taewon Lim
Keyword(s):  
Water Management ◽  
Fuel Cell ◽  
Polymer Electrolyte Membrane ◽  
Gas Diffusion ◽  
Fuel Cell Vehicle ◽  
Performance Loss ◽  
Electrolyte Membrane ◽  
Catalyst Layers ◽  
Diffusion Layers ◽  
Water Behavior

The PEMFC (Polymer Electrolyte Membrane Fuel Cell) requires well hydration for acceptable protonic conductivity, but liquid water in the catalyst layers and gas diffusion layers can cause performance loss due to blockage of reactants to the catalysts. Many activities have been done on the water management in PEMFC stack to guaranty better performance and its longevity. Some approaches for PEMFC stack in Hyundai-motor will be shown in this presentation based on analytic modeling, CFD, and experiment, then some challenges for better understanding of water behavior in PEMFC will be shown at the end of this paper.

Effects of Microhydrophobic Porous Layer on Water Distribution in Polymer Electrolyte Membrane Fuel Cells

2013 ◽  
Vol 11 (1) ◽  
Author(s):  
Farzad Ahmadi ◽  
Ramin Roshandel
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Cathode Side ◽  
Two Phase ◽  
Fuel Cell Performance ◽  
Electrolyte Membrane

Performance of polymer electrolyte membrane fuel cells (PEMFC) at high current densities is limited to transport reactants and products. Furthermore, large amounts of water are generated and may be condensed due to the low temperature of the PEMFC. Development of a two-phase flow model is necessary in order to predict water flooding and its effects on the PEMFC performance. In this paper, a multiphase mixture model (M2) is used, accurately, to model two-phase transport in porous media of a PEMFC. The cathode side, which includes channel, gas diffusion layer (GDL), microporous layer (MPL), and catalyst layer (CL), is considered as the computational domain. A multidomain approach has been used and transport equations are solved in each domain independently with appropriate boundary conditions between GDL and MPL. Distributions of species concentration, temperature, and velocity field are obtained, and the effects of MPL on species distribution and fuel cell performance are investigated. MPL causes a saturation jump and a discontinuity in oxygen concentration at the GDL/MPL interface. The effect of MPL thickness on fuel cell performance is also studied. The results revealed that the MPL can highly increase the maximum power of a PEMFC.

Pore Network Modeling to Study the Effects of Common Assumptions in GDL Liquid Water Invasion Studies

2012 ◽  
Author(s):  
J. Hinebaugh ◽  
A. Bazylak
Keyword(s):  
Liquid Water ◽  
Polymer Electrolyte Membrane ◽  
Three Dimensional ◽  
Pem Fuel Cells ◽  
Pore Network ◽  
Gas Diffusion ◽  
Ex Situ ◽  
Network Modelling ◽  
Electrolyte Membrane ◽  
Inlet Conditions

Topologically equivalent pore network modelling of polymer electrolyte membrane (PEM) fuel cell gas diffusion layer (GDL) materials was employed to simulate ex-situ liquid water invasion experiments commonly conducted to investigate multiphase transport in PEM fuel cells. Stochastic, three dimensional pore spaces are numerically reconstructed to mimic carbon fibre paper based GDL materials. A watershed based method was used for extracting pore networks from a range of sample sizes. Invasion percolation was employed to simulate liquid water originating at one surface of the material and percolating through to the opposite surface. Inlet reservoir areas were chosen to mimic those used in ex-situ experiments in literature. It was found that sample size has a strong overall effect on saturation levels and inlet conditions primarily affected saturation near the inlet.

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