Performance enhancement of metal hydride hydrogen storage reactors through synergistic coupling of metal foam and tree-shaped fins

To address the critical issues of slow hydrogen absorption rate and insufficient utilization of storage capacity in metal hydride (MH) reactors caused by poor thermal conductivity, this study introduces a spatially coupled heat transfer enhancement design that combines high-porosity metal foam (MF) with tree-shaped fins (TSF). Systematic numerical simulations are performed to evaluate the hydrogen charging performance of the proposed reactor configuration. Results show that the synergy between the TSF-induced directional thermal backbone and the MF-based spatially distributed heat diffusion network yields a substantial improvement: 90% saturation is achieved 17.4% faster than with the MF-only configuration and 11.7% faster than with the TSF-only counterpart. The effects of MF porosity and TSF volume fraction on hydrogen storage performance are subsequently investigated. The optimal total volume fraction of high-thermal-conductivity material (HTC) is found to be approximately 10%, and an optimal volume ratio between TSF and MF is identified under varying total filling volumes. On this basis, a comprehensive evaluation system ( CES ) encompassing multiple indicators, including gravimetric/volumetric hydrogen storage density, reaction rate, is established. This study provides theoretical foundations and engineering guidance for the thermal design of high-efficiency, compact MH reactors.