Numerical analysis of heat transfer and stresses in a packed bed of hydrogen storage alloys with expansion

In this study, heat transfer and stresses in tanks and packed beds of hydrogen storage alloys with expansion were numerically analyzed by the finite element method to investigate the effect of dimension (height and radius) on stresses with hydrogen absorbing fraction in the cylindrical packed beds and tanks. First, temperature and hydrogen absorbing fraction in the packed beds were calculated respectively. Then hydrogen absorbing fraction distributions were used to calculate the stress in the tank and the packed bed, assuming the alloy's volume expansion ratio is linear to hydrogen absorbing fraction and is isotropic for each axis. As a result, it is shown that hydrogen absorption begins at the wall side, where the heat can be removed efficiently by coolants. The maximum wall stress of all tanks increases with a raise in hydrogen absorbing fraction in the packed beds. The dimension of all the packed beds and all the hydrogen absorbing fractions significantly influences on the maximum wall stress.