Study of coupled heat and mass transfer during absorption of hydrogen in MmNi4.6Al0.4 based hydrogen storage device

Abstract

A two-dimensional numerical analysis of coupled heat and mass transfer processes in a cylindrical metal hydride reactor containing MmNi4.6Al0.4 is presented. To understand the hydrogen absorption mechanism the governing equations for energy, momentum and mass conservation and reaction kinetic equations are solved simultaneously using the finite volume method (FVM). Performance studies on MmNi4.6Al0.4 based hydrogen storage device are carried out by varying the hydrogen supply pressure, absorption (cooling fluid) temperature, overall heat transfer coefficient and hydride bed thickness. Effect of convection terms in the energy equation on hydrogen storage performance is found to be negligible. The results obtained from the computer simulation showed good agreement with the available experimental data. At the supply conditions of 30 bar and 298 K, MmNi4.6Al0.4 stores about 1.28 wt%, which is very close to the experimental value of 1.3 wt%. Overall high heat transfer coefficients are found to reduce the absorption time significantly. © 2009 Indian Academy of Sciences.