Numerical simulation of droplet dynamics in a proton exchange membrane (PEMFC) fuel cell micro-channel

• LB simulations were used to understand the droplet dynamics in gas micro-channels.
• Effect of different parameters on the droplet behavior is examined.
• Droplet evacuation is faster for a hydrophobic micro-channel than a hydrophilic one.

Water management is emerging as one of the problems related to Proton Exchange Membrane Fuel Cell. In fact, the humidity in a PEMFC plays a key role on its performance. The membrane must be sufficiently moistened to ensure the transport of protons. However, liquid water may form and block the transport of gas to the electrodes. This can generate a sharp decrease in current produced by the cell.In this paper, the droplet behavior in a proton exchange membrane (PEM) fuel cell micro-channel was simulated by using the lattice Boltzmann method (LBM) based on the Shan-Chen Pseudo-potential model. A three-dimensional case was considered and a D3Q19 scheme was utilized to keep track of the deformation of the liquid–gas interface. Visualization of droplet shape is obtained for different capillary numbers and the hysteresis between the advancing and receding contact angle is clearly observed. Also flow structures in the micro-channel were illustrated. The effect of wettability on droplet displacement behavior is also explored. It was found that hydrophobic micro-channel is better than the hydrophilic micro-channel for droplets evacuation. This work presents a basic understanding for the droplet behavior in a fuel cell micro-channel and the effect of important parameters on its dynamics.