The lattice Boltzmann method simulation of gas purge in flow channel with real GDL surface characteristics for proton exchange membrane fuel cell 2019-01-0389
Gas purge is considered as an essential shutdown process for a PEMFC (Proton Exchange Membrane Fuel Cell), especially in subfreezing temperature. The water flooding phenomenon inside fuel cell flow channel have a marked impact on performance in normal operating temperature. In addition, the residual water ices in the subzero temperature, thus blocking the mass transfer from flow channel to porous media. Therefore, the gas purge course is of primary importance for improvement of performance and durability. The water droplet resides in the flow channel can be moved out due to shear force of gas. In fact, the flow channel is not completely even due to surface roughness of gas diffusion layer (GDL) and the water droplet may not move along the flat surface. Moreover, the water droplet may block the flow channel and then be sheared into films on the surface of flow channel. The lattice Boltzmann method (LBM), based on the mesoscopic kinetic theory, has recently become a powerful simulation tool for multiphase flow. The main advantages of LBM over traditional computational fluid dynamics (CFD) include capacity for investigating complicated geometries, simple implementation, high computation efficiency and easy implementation of parallel-processing. In the present work, the multicomponent multiphase lattice Boltzmann (LB) model is developed and applied to simulate the gas purge process in the flow channel with real GDL surface characteristics for PEMFC. The real GDL surface characteristics (concave and convex, wettability and non-wettability) and situation of totally blocked flow channel by water droplet is investigated mainly. We hope to have a better understanding of gas purge mechanism from a mesoscopic way.
Peng Xu, Sichuan Xu, Pengcheng Liu, Xingyu Liu