For better water management in gas channels (GCs) of polymer electrolyte fuel cells (PEFCs), a profound understanding of the liquid water dynamics is needed. In this study, we propose a novel geometrical setup to conduct a series of direct simulations of the liquid water dynamics in a GC. The conducting pathways in the gas diffusion layer (GDL) are simplified by three cylindrical pipes connected to a liquid water reservoir representing the catalyst layer (CL). The droplet dynamics, corner film dynamics, and the competition between the film and droplet flows in the GC are explored in detail. The results show that the three-phase contact line plays an important role in resisting the gas drag force for a droplet movement in the GC. The gas drag force can dominate the film flow along the GC corners, and a proper selection of the contact angle of the GC sidewalls is necessary to balance two requirements: increasing the film removal ability and removing the water clogging fast. The competing mechanisms of the droplet and film flows give us the possibility to regulate liquid water flow into GCs, and maybe lead to a better water management in GCs. Finally, the results from this work also serve to provide insights into the development of a phenomenological model for the liquid water flooding in GCs.
Chaozhong Qin, Dirk Rensink, S. Majid Hassanizadeh, and Stephan Fell
The time multiplexed deep silicon etch (TMDSE) process is the etch process of choice to make MEMS devices and through wafer vias. It has been used to produce deep trenches and vias at reasonable throughputs. Significant issues remain for the TMDSE process as well as room for improvement eve ... more
The growth, composition, electrical characteristics, and reliability performance of high-k HfO2 dielectric films that were deposited by an atomic layer deposition technique are studied. The films were grown using tetrakis(ethylmethylamino)hafnium precursor and either H2O or ozone (O3) as th ... more
Zinc oxide (ZnO) thin films have attracted significant attention for application in thin film transistors (TFTs) due to their specific characteristics, such as high mobility and transparency. In this paper, the authors fabricated TFTs with ZnO thin films as channel layers deposited by plasm ... more