Boil-Off Rate Behavior in a Double-Shell Vacuum-Insulated Cryogenic Storage Tank with Multilayer Insulation

Cryogenic storage systems require precise management of boil-off gas (BOG) to prevent pressure buildup caused by external heat ingress. This study investigates sloshing-induced heat transfer and BOG generation in a double-shell vacuum-insulated cryogenic storage tank subjected to dynamic excitation. Experiments were conducted under dynamic operating conditions, during which BOG generation and boil-off rate (BOR) were measured over a range of vibration frequencies, acceleration levels, and fill ratios. The results reveal a strong frequency-dependent sloshing behavior that significantly influences BOG generation. Under dynamic conditions, the BOR exhibited a non-linear dependence on filling ratio, with a maximum response occurring at 50% filling, reflecting an optimal balance between sloshing-enhanced heat transfer and geometric confinement. Based on the experimental observations, an integrated numerical heat transfer model incorporating multilayer insulation (MLI) performance and vacuum level effects was developed and validated against experimental data. The validated numerical model successfully predicts pressure evolution and BOG generation under operational sloshing conditions, providing valuable insights for optimizing cryogenic tank design and minimizing boil-off losses.