Multiphase Mass Transport in Channels and Porous Media

5 MULTIPHASE MASS TRANSPORT IN CHANNELS AND POROUS MEDIA  

Mixed liquid/gas-phase flow can occur in direct alcohol and hydrogen polymer electrolyte fuel cells. For the hydrogen fuel cell, liquid water can build up in either the anode or 

The phases are classified according to the superficial gas and liquid velocity. The superficial gas-phase velocity can be written as 

Because the various flow regimes are quite complex, a generally unified treatment of the flow patterns does not exist, and the background knowledge is taken from experimental studies of oil-air, oil-water, or water-oil flow in much larger pipes than the relatively 

Multiphase flow in porous media is a very important topic for low-temperature PEFCs because water produced at the cathode flows through the porous catalyst layers and porous gas diffusion media. Any local blockage of normally open pores restricts reactant flow to the reaction sites, a phenomenon known as flooding. The water balance and flooding in a PEFC is described in detail in Chapter 6. Here, the basic fundamentals that describe two-phase flow in porous media are described to guide and understanding. 

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Multiphase Mass Transport in Channels and Porous Media 239... 

Multiphase Mass Transport in Channels and Porous Media 245 Flow of the liquid phase in fuel cell porous media is driven by several forces ... 

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