Objective Metal hydrides suffer from low thermal conductivity, and their highly exothermic hydrogen storage process impedes reaction kinetics. This paper focuses on the thermal management of hydrogen storage reactors, investigating the impact of geometric parameters on storage performance.

Method By developing a two-dimensional numerical model of a finned tube bundle hydrogen storage reactor, this study investigated the effects of reactor radius and wall thickness on the hydrogen absorption rate and the formation of reaction dead zones. Optimal wall thicknesses were determined for various reactor radius, which then served as the basis for a parametric study to identify optimized hydrogen storage conditions.

Result The results indicate that increasing the reactor wall thickness enhances the hydrogen absorption rate and shrinks the reaction dead zones near the bed periphery. For a reactor with a 25 mm radius, an optimal wall thickness of 5 mm yields a near-minimum absorption time of approximately 300.0 s. For radius of 35~55 mm, the optimal thicknesses are 10 mm, 15 mm, and 15 mm, respectively, with the corresponding absorption times varying by less than 1.69%. However, for radius exceeding 55 mm, further increasing the wall thickness is no longer an effective strategy for optimizing the dead zone. Furthermore, the optimized operating conditions—a storage pressure of 1.2 MPa, a heat transfer fluid temperature of 283.15 K, and a convective heat transfer coefficient of 2500 W/(m²·K)—shortened the absorption time by 39.44% compared to the initial conditions.

Conclusion Optimizing the reactor wall thickness can effectively eliminate reaction dead zones in finned tube reactors across a range of radius. These findings provide valuable guidance for the engineering design and application of metal hydride hydrogen storage reactors.