A CFD Comparison of Interfacial Phase Change Models for Boil-off, Self-pressurisation and Thermal Stratification in Liquid Hydrogen Storage Tanks

Liquid hydrogen (LH2 ) is a promising energy carrier for future clean fuel technologies. However, its cryogenic storage and handling pose significant challenges, particularly due to self-pressurisation and boil-off from ambient heat ingress. Accurate modelling of these phenomena is essential for the safe and efficient design of LH2 storage systems. A key aspect of such modelling is the selection and implementation of an appropriate interfacial phase change model. This study presents a comparative assessment of three widely used phase change models; the Schrage model, the Modified Energy Jump (MeJ) model, and the Lee model. A parametric study was conducted across three coefficients for each model, with validation performed against five experimental benchmark cases from NASA’s K-Site and MHTB cryogenic tanks, focusing on planar interface problems with thermally induced phase change under normal gravity. A CFD approach using STAR-CCM+ was employed to evaluate each model’s ability to predict tank pressure, temperature, and boil-off behaviour. The Schrage model demonstrated the most robust and accurate results, exhibiting minimal sensitivity to coefficient variation and offering both numerical stability and physical fidelity. It demonstrated a maximum mean absolute percentage error (MAPE) of just 3.0% in its pressurisation predictions. The MeJ model showed comparable accuracy when its heat transfer coefficient was appropriately selected, highlighting its reliance on an empirically derived coefficient. In contrast, the Lee model performed the poorest, exhibiting numerical divergence at high coefficient values and substantial deviation in its prediction of self-pressurisation, with errors of up to 11% MAPE. These findings provide practical guidance for the selection and implementation of phase change models in CFD simulations and highlight key considerations for modelling LH2 storage tanks in industrial applications.