Analysis for packing state of the packed bed of hydrogen storage alloy using discrete element method

Numerical analysis was performed by Discrete Element Method in consideration of expansion and contraction of particles to investigate the stress developed on the wall in the vessel of the packed bed of hydrogen storage alloy. For the packed bed composed of the spherical particles with a diameter of 2 and 7 mm, the effect of the expansion and contraction of the particles on the packing ratio and the stress developed on the wall was investigated. It was shown that smaller particles moved through the gaps between the particles by repeating expansion and contraction of particles, and the packing ratio and the stress became higher at the lower part of the packed bed. The effect of the expansion and contraction of the particles on the packing ratio and the stress developed on the wall in the vessel was also examined for the packed bed composed of the spherical, tetrahedral or cubic particles. The packing ratio in each region and the stress developed on the wall in the vessel were different depending on the shape of particles. From these results, it was shown that the shape and the movement of the particles affect the stress developed on the wall.