Abstract
The article presents a zero-dimensional mathematical model of a tubular fuel cell and its verification
on four experiments. Despite the fact that fuel cells are still rarely used in commercial applications,
their use has become increasingly more common. Computational Flow Mechanics codes allow to predict
basic parameters of a cell such as current, voltage, combustion composition, exhaust temperature,
etc. Precise models are particularly important for a complex energy system, where fuel cells cooperate
with gas, gas-steam cycles or ORCs and their thermodynamic parameters affect those systems.
The proposed model employs extended Nernst equation to determine the fuel cell voltage and steadystate
shifting reaction equilibrium to calculate the exhaust composition. Additionally, the reaction of
methane reforming and the electrochemical reaction of hydrogen and oxygen have been implemented
into the model. The numerical simulation results were compared with available experiment results
and the differences, with the exception of the Tomlin experiment, are below 5%. It has been proven
that the increase in current density lowers the electrical efficiency of SOFCs, hence fuel cells typically
work at low current density, with a corresponding efficiency of 45–50% and with a low emission level
(zero emissions in case of hydrogen combustion).
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