A Comparison Between Two Hydrogen Injection Modes in a Metal Hydride Reactor

The optimization of hydrogen storage within metal hydride reactors is one of the main issues in the recent works. The aim of this paper is to compare between two hydrogen injection modes within a hydrogen tank in terms of heat transport. The charging process in the cylindrical tank is releasing heat because it undergoes an exothermic reaction. In order to guarantee a maximum absorption of hydrogen from the alloy (LaNi5), a heat exchanger along the cylindrical walls is considered. Two hydrogen injection modes have been considered in this study: (1) injection from the top, (2) injection from the axis of the cylinder. The governing equations based on mass, heat and momentum balances are transient and two-dimensional. The results show that axial injection is more advantageous than the top one, since it ensures a better heat transfer within the hydride bed and therefore helps to absorb the maximum amount of hydrogen in a shorter time.