Abstract:
The purpose of this work is to numerically study the dynamic behavior of heat and mass
transfer in an annulus-disc metal hydride reactor used for hydrogen solid storage. A twodimensional mathematical model of a simple geometry consisting of the equations governing the phenomenon of hydrogen storage has been proposed, in which the Navier-Stokes equations were used in addition of the source term with the Forchheimer’s modification, to adequately describe fluid flow in the packed bed considered as porous medium. The equations of continuity, momentum and energy were solved using the finite volume method; by accommodating the commercial code ANSYS FLUENT through user-defined functions (UDF), to numerically solve the equations governing the sorption processes studied.
The numerical model results were compared to experimental results reported in the literature for the case of a simple regular geometry. A good agreement was found between present calculations results and experimental data.
Numerical simulations have shown that the pressure drop in the metal hydride packed bed
caused by the fluid inertia can be considerable in this flow type. Moreover, the hydrogen sorption time depends on the configuration and geometrical dimensions of the heat exchange device. Thus, the minimization of absorption or desorption time is reduced to the reliability of the heat exchange process in the packed bed reactor. In addition, the conductivity is a key factor in the efficient design of the metal hydride reactors.
