Latent heat-assisted thermal management of a metal hydride hydrogen storage reactor using novel shape-stabilized composite phase change material slurry

This study introduces a novel cooling strategy based on a phase change slurry (PCS) integrated with advanced encapsulated core–shell phase change materials (PCMs), uniquely tailored to achieve simultaneous enhancement of thermal regulation and hydrogen uptake performance. To model the complex thermo-hydrodynamic interactions, a two-dimensional axisymmetric numerical framework is established using a mixture multi-phase Eulerian–Eulerian approach, which enables comprehensive analysis of energy transport between the water carrier fluid and composite PCMs. The phase transition of PCMs is rigorously incorporated through a specific heat capacity formulation, allowing precise representation of latent heat effects within the PCS domain. A comprehensive parametric analysis is performed to evaluate the effect of key nanoparticle design criteria—PCM type, shell thickness, shell material, and core size—on the MH reactor’s thermal and hydrogenation capability. Compared to conventional water cooling, PCS-based configurations significantly improve heat dissipation and accelerated hydrogen absorption. Among the tested configurations, the Ag-shelled n-Octadecane PCS achieves the fastest saturation time (300 s), outperforming the water-cooled baseline (700 s). Other PCS designs, including graphite- and SiO 2 -shelled particles, also demonstrate enhanced thermal behavior depending on their thermal conductivity and phase change characteristics. This study represents the first in-depth numerical investigation of flowing PCS as an active thermal regulation strategy for MH systems. The findings highlight the potential of PCS to overcome thermal limitations associated with conventional cooling techniques and pave the way for the establishment of more effective, compact, and responsive hydrogen storage technologies.