Numerical analysis of heat and mass transfer during hydrogen absorption in metal hydride beds with a novel peridynamic model

Abstract

Numerical modelling and study of metal hydride bed with heat and mass transfer is a key to identify and predict the state of the storage device during absorption and desorption process. It is a great challenge to numerically study this problem considering cracks and volumetric expansion for conventional approaches due their limitations in treating discontinuities and large deformations. To effectively predict the hydrogen charging performance with the influences of cracks and volumetric expansion, a novel peridynamic (PD) model considering hydrogen absorption was proposed, which has not been used in most existing studies. The developed PD model was applied to simulate metal hydride reaction including depleted uranium (DU) and zirconium cobalt (ZrCo) in a thin-layer bed. The simulation results agreed well with both existing numerical solutions and experimental observations. The cracks were introduced to identify their influences on the performance of hydrogen absorption in a DU bed as a prototype. It is demonstrated that crack length and location had a significant influence on the absorption rate and average temperature evolution. With the increase in the crack length, the hydrogen absorption efficiency of the metal hydride bed (MHB) decreases dramatically due to the high bed temperature. The crack approaching the cooling boundary would greatly affect the temperature evolution, which causes the average H/M value to reach saturation later. Finally, the effects of the volumetric expansion were taken into consideration in the present PD model. Unlike ZrCo, the hydrogen kinetics performance would be overrated due to the neglection of the volumetric expansion in a DU bed.