The rational approximation method in the prediction of thermodynamic properties for SOFCs

The aim of this work is to present the method of rational approximation as an alternative technique for finding empirical models for thermophysical properties of relevant fluids to solid oxide fuel cells (SOFCs). The method of rational approximation is used here for calculating the isobaric heat capacity, the entropy of formation, the enthalpy, the Gibbs energy of formation, the thermal conductivity and the dynamic viscosity, at 0.1 MPa, of important gases in SOFCs (CH4, C2H6, C3H8, CH3OH, C2H5OH, CO2, CO, H2, H2O, O2, N2, NH3). Rational approximations are well known for their ability to extrapolate, and this has been the main reason for adopting the method in this paper, since it is often difficult and expensive to have experimental data in the entire range of interest. A data survey was conducted for collecting the required information, and finally 75 rational approximations were generated all with a coefficient of determination of R2=99%.