Oscillation of water droplets for enhanced water removal from the gas flow channels of fuel cells  This invention includes a means for providing cyclic force to a water drop on the surface of a fuel cell component at or near the drops natural frequency of the water drop. The droplet is caused to oscillate at a frequency that the liquid inertial forces produced by the oscillation are sufficient to overcome the force of contact line pinning at the solid/liquid/gas interface.
The function of this invention is to assist with the removal of product water from the gas flow channels of a fuel cell. Product water forms on surface of the gas diffusion layer of a fuel cell as a result of fuel cell operation. The product water migrates through the gas diffusion layer into the gas flow channel. The water drops are moved through the channel to the exit via the gas flow. The movement of the water drops is inhibited by pinning of the three-phase region commonly referred to as the contact line region; that is, the line of contact where the gas, liquid, and solid coincide. Efficient removal of this product water is currently a technical challenge and is an important step in fuel cell operation and effective product water removal is a barrier to increased commercial utilization of fuel cells.
A balance between keeping the membrane from becoming too dry or too wet must be maintained for efficient and reliable operation. At high current densities, the production of liquid water may exceed the capacity of the gas streams to evaporate the water out of the fuel cell stack and drops of water will appear within the gas flow channels. If the water accumulation becomes too great, then the gas flow channel may become completely blocked by water and the fuel cell will "flood". The water drops must be removed from the gas flow channels for reliable operation. |
Fuel Cell Group This group is a multi-disciplined team focused on fuel cell heat recovery and fuel cell conversion efficiency improvement. These thrust areas are linked to a set of topics within which the group possesses expertise including heat recovery, initial start issues of high temperature fuel cells, high thermal and/or electrical conductivity materials, energy density, weight, and space related issues, high temperature membranes. low cost high energy cathode/anode, hydrogen generation, storage, transportation, and safety, fuel reforming, low CO emission, long life high power density battery development and hybrid battery. |
Examining Biomass Substrates in Ethanol Production as Source of Alternative Fuel  Bio-fuel ethanol as an alternative fuel is gaining interests for environmental and economical reasons. To reach ethanol goals needed in the United States, it will be essential to take advantage of various biomass substrates for ethanol production (e.g. agricultural and industrial waste products). Recent work includes study of the growth inhibitor, furfural, which induces cellular stress signals in Saccharomyces cerevisiae. Using various fluorescent indicators and transmission electron microscopy techniques, it was determined that furfural causes an increase in reactive oxygen species accumulation, cellular membrane damage (vacuole and mitochondrial membranes), chromatin damage, and cytoskeletal damage in wild-type S. cerevisiae. Whether or not overexpressing any of the previously identified genes will reduce oxidative damage is being investigated. |
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