Thermal analysis of baffle effects in cryogenic hydrogen tanks

Abstract

Minimizing heat ingress into cryogenic storage tanks is a key challenge in thermal system design. While prior studies have examined insulation materials or baffle effects in isolation, the coupled influence of these mechanisms on overall thermal resistance remains underexplored. This study introduces a novel approach that parameterizes baffle geometry and size and couples it with insulation performance by evaluating how baffle configurations influence both internal convection and insulation resistance in a two-phase cryogenic hydrogen tank. A 2D axisymmetric model at 50 % fill level is simulated under transient conditions using commercial multiphysics simulation software, with the working fluid initially at saturation temperature and standard atmospheric pressure. The model is validated against experimental LH₂ tank studies, with strong agreement in both liquid and vapor phase temperature trends. Increasing circular ring baffle diameter from 1 meter to 2 meters reduces the average Nusselt number by 16 %, velocity magnitude by 44 %, and vorticity magnitude by 17 % compared to the no-baffle case. The optimal 2 m baffle is used to assess insulation-baffle coupling, revealing that baffle inclusion increases the convective-to-conductive resistance ratio by up to 30 % at low insulation thermal conductivities but diminishes to 4 % as conductivity rises. Geometric analysis shows that curved baffles outperform rectangular designs through smoother boundary layer development, stabilizing flow, and suppressing convective transport. These findings establish that thermal performance in cryogenic tanks depends on coupled design variables, underscoring the need to jointly optimize baffle structure and insulation properties rather than treating them as isolated components.