Modeling Of Gas And Water Transport In Serpentine Flow Field Of PEM Fuel Cell

Proton exchange membrane (PEM) fuel cell has a lot of virtues, such as high power density, high-energy efficiency, low-temperature operation, fast start-up and zero-emission. As a kind of new energy source, more and more people pay attention to PEM fuel cell.At present, the serpentine is the most commonly used flow field. This paper uses computational fluid dynamics software Fluent to simulate the serpentine flow field PEM fuel cell and analysis the reactant and the resultant transfer in the fuel cell. Thus provides certain instruction to the fuel cell design and work.First, the basic theory of fuel cell is described. A three dimension mathematical model is described to model the working process of PEM fuel cell, it accounts simultaneously for the fluid flow, electrochemical reaction in the catalyst layer, gas diffusion in the porous media and the VOF (Volume of Fluid) model for the water transport in the gas channel.Then, the serpentine flow field fuel cell with the tapered channel is simulated and analyzed. The results show that the tapered channel is advantageous to the reactant transmission, water extraction, and finally enhance the fuel cell performance. However, the pressure drop has also increased in the flow field, a best ratio about tapered channel should be explored from the fuel cell overall efficiency.Then, the uniform distribution about the gas and water are analyzed by changing the gas inlet mode or the arrangement patter of the channel in PEM fuel cell with the two serpentine channel. The results show that the two means are advantageous to the uniform distribution about the gas and water in the fuel cell, and enhance the fuel cell performance, especially at the higher current density.Finally, the water transport in the flow channel is simulated and analyzed by using the VOF model of the Fluent software. Investigation on the dynamic behavior of liquid water entering a channel through a pore in the bottom wall is reported in the paper, by changing the hydrophilic/hydrophobic nature of the surface of gas diffusion layer(GDL), the size of water pore, the speed of the inlet air, the speed of the injecting water. The results show that the hydrophobic nature of the surface of GDL, smaller water pore, higher speed of the inlet air are advantageous to discharge liquid water; Lower speed of the injecting water reduced the speed of the water production. Then, the dynamic transport of liquid water in the serpentine channel is studied. The effects of channel bend and hydrophilic/hydrophobic properties of serpentine channel of PEM fuel cell on water behaviour are discussed. The result show that the round bend and the hydrophilic channel wall are advantageous to discharge liquid water.