Experimental and numerical evaluation of multilayer insulation for liquid hydrogen storage

Multilayer insulation (MLI) is the primary technology used to suppress heat ingress and reduce boil-off in large-scale liquid hydrogen (LH 2 ) storage. Although MLI can achieve very low effective conductivity under high vacuum, its pressure-dependent performance remains insufficiently characterized for practical operating conditions. The thermal behavior of aluminum foil and glass fiber MLI (30 layers, ≈ 1 layer/mm) was characterized from 760 Torr to 1 × 10 −7 Torr using boil-off calorimetry, analyzed with Lockheed and McIntosh models incorporating Knudsen-based gas conduction, and validated through finite element simulations of a 760 L double-shell tank. Distinct pressure-dependent regimes were identified: the effective thermal conductivity ( k eff ) decreased from 22.2 mW m −1 K −1 at atmospheric pressure to 0.4–0.5 mW m −1 K −1 under high vacuum, consistent with the transition from gas conduction to radiation-dominated transfer. Knudsen-corrected formulations reproduced measurements within ±10 % across 10 −2 –10 −4 Torr, the pressure range most relevant to industrial LH 2 tanks. Finite element analysis using measured or model-derived k eff predicted boil-off rates within −2.8 % to −4.9 % of experiment, achieving overall accuracy within ±5 %. The integrated methodology provides validated k eff relations and a coupled experimental–computational framework for the design, verification, and long-term operation of LH 2 storage and transfer systems.