Thermal aspects energy equations

The multi-physics of SOFCs are governed by the mass, momentum, and energy conservation equations, and the chemistry and electrochemistry. The governing equations of SOFCs are tightly coupled and changes to one aspect of the fuel cell can drastically affect another. For example, the rate and composition of the fuel flow in the anode will affect the temperature distributions in the cell, which can induce stresses due to mismatches between the coeSicients of thermal expansion of the various layers in the SOFC. The fuel flow wiU also affect the overall performance of the fuel cell based on the distribution of species in the anode and the electrochemical reactions. 

It was clear, even from the classical electromagnetic theory, that a field which interacts with matter and imparts energy and momentum must itself carry energy and momentum. Classical expressions for the energy and momentum associated with the electromagnetic field can be found in texts on electromagnetic theory. To understand the thermodynamic aspects of radiation, we need an equation of state, i.e. an equation that gives the pressure exerted by thermal radiation and its relation to the temperature. 

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