Correlations for prediction of hydrogen gas viscosity and density for production, transportation, storage, and utilization applications

Accurate determination of hydrogen transport properties is essential for hydrogen pro-duction, transportation, storage, and utilization. Different Equations of State (EoS) are commonly used to calculate hydrogen thermophysical properties. However, EoS ap-proaches are usually implicit and require numerous calculations and could be very time consuming. Therefore, the end users often desire the predictions of thermophysical properties using simple empirical correlations, which can be considered a practical solu-tion to reduce the computational burden of EoS calculations. This study presents new explicit empirical correlations using symbolic regression analysis of available experimental data to calculate hydrogen viscosity and density. The developed viscosity correlation provides accurate predictions over the temperature range of 100-2130 K for dilute gas and 14 (H2 triple point)-1000 K for hydrogen gas up to 220 MPa. The results show an average absolute deviation (AAD) of 1.06% in the predicted gas viscosity, with the largest deviation in the vicinity of the critical point. The dilute gas viscosity was also predicted with an AAD of 0.467%. The density correlation represents a high prediction accuracy with an AAD of 0.26% over the temperature and pressure ranges of 150-423 K and 0.1-220 MPa, respectively. The developed correlations offer a higher prediction accuracy and find applications in hydrogen production, transportation, storage, and utilization value chain.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.