Towards accurate modeling of transport properties of supercritical hydrogen using entropy scaling theory and improved volume-translated cubic equations of state

• Couple entropy scaling theory with CEOSs and improved volume-translated CEOSs. • Consider wide temperature/pressure ranges encountered in hydrogen-based systems. • Our models yield good accuracy in predicting transport properties of hydrogen. • Our models exactly replicate the true critical volume of hydrogen. Hydrogen is an important energy source due to its renewability, high energy density, and clean combustion. Accurate prediction of transport properties of hydrogen is crucial for the design and optimization of various hydrogen-based energy systems. In this study, we combine the entropy scaling theory with four cubic equations of state (CEOSs) (including the original Soave-Redlich-Kwong EOS (SRK EOS) and Peng-Robinson EOS (PR EOS), as well as the volume-translated SRK EOS (VT-SRK EOS) and volume-translated PR EOS (VT-PR EOS) proposed in our previous work), leading to the development of various entropy-scaling-theory-based transport property models. Compared to the conventional models, the entropy scaling theory integrated with our previously proposed models is capable of more accurately predicting the transport properties of hydrogen at pressures from triple-point pressure (i.e., 0.01 MPa) to 300 MPa and temperatures from critical temperature (i.e., 33.15 K) to 600 K. More specifically, the models coupled with the VT-SRK EOS yield %AADs of 3.09, 5.03, and 3.19 in predicting viscosity, thermal conductivity, and self-diffusion coefficient, respectively. The proposed models combined with the VT-PR EOS also perform well in predicting these three transport properties, achieving %AADs of 2.96, 4.94, and 2.43, respectively. It is worthwhile mentioning that the VT-SRK EOS and VT-PR EOS can completely reproduce the true critical volume of hydrogen. We believe the good accuracy and broad applicability of the models proposed in this work can make it a powerful tool for modeling the transport properties of hydrogen under diverse conditions encountered in practical hydrogen-based energy applications.