Numerical Investigation of Spiral Tubes and Turbulators for Enhanced Metal Hydride Reactors

Solid-state hydrogen storage is severely limited by poor thermal performance of storage reactors, which leads to non-uniform temperature fields and slow reaction kinetics. A numerical model for metal hydride hydrogen storage technology was implemented by means of COMSOL Multiphysics 6.3, based on hydrogen sorption behavior for LaNi5-based material. After experimental validation, a spiral-wound tube with embedded turbulators was introduced into the reactor. The influence of turbulator cross-sectional ratio and shape on hydrogen-absorption performance was then investigated. When the turbu-lator occupied 1/40 of the cross-section, the temperature distribution became more uniform and the reaction rate increased markedly; the time to achieve 80% conversion was reduced by approximately 9.29%. The study demonstrates that tailoring the turbulator geometry (circular vs. square) and exploiting its synergy with the spiral tube accelerates reaction kinetics and balances the temperature field. Under 0.8 MPa and 313 K, a hydrogen uptake of 1.4 wt% was achieved. The simple structure can be mass-produced by CNC (Computer Numerical Control) tube-bending, making it attractive as a portable hydrogen source for mobile devices such as unmanned aerial vehicles.