Boil-Off Gas Generation Characteristics of Liquid Hydrogen in a Type-C Tank Under Sloshing Conditions: Effects of Filling Ratio, Excitation Parameters, and Baffles

Liquid hydrogen (LH2) is a promising energy carrier for maritime transportation owing to its high storage density and carbon-free utilization. However, its cryogenic storage temperature inevitably causes boil-off gas (BOG) generation, even with advanced insulation, and ship-induced sloshing can further disturb interfacial heat and mass transfer. This study numerically investigates BOG generation in a Type-C LH2 tank under sloshing conditions. A transient two-phase CFD model was developed using the volume of fluid method to track the liquid–vapor interface and the Lee phase-change model to calculate evaporation and condensation. Sloshing excitation was imposed through mesh motion, and parametric simulations were performed for different filling ratios, frequencies, amplitudes, and baffle configurations. The results show that the 50% filling condition produced the lowest boil-off rate, while amplitude had a stronger influence than frequency by increasing free-surface deformation, internal velocity, and convective heat transfer. Baffles reduced liquid motion but could increase BOG through additional conductive heat-transfer paths. These findings support BOG prediction and baffle design for Type-C LH2 tanks.