Heat flux current regime

With the general relation for the activation overpotential in the oxygen-transport-free regime (4.142), an explicit dependence of the heat flux on the cell current density... 

Heat flux from the catalyst layer (W cm ). Equation 4.298 Heat flux from the CL in the high-current regime (W Equation 4.294... 

While the model presented applies to a wide range of PEM fuel cell operational regimes there are some caveats to its application. We assume the flux of gas and heat out of the catalyst layer scale with the current density. This would not be the case, for example, with a dry anode feed and a wet cathode feed, which would generate water transport independent of the current level. We assume there is no lateral pressure gradient imposed in the x direction across the GDL such as would arise in interdigitated or serpentine flow fields we consider straight flow fields. 

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