A tool for modelling the breathing of hydride powder in its container while cyclically absorbing and desorbing hydrogen

Effect of glidants on LaNi5 powder flowability

“…One approach to avoid the build-up of tensions in the container walls is to allow the material to flow and accommodate as it swells during hydrogen absorption [20] in a rigid container, failure to do so will result in tension accumulation in the walls and, eventually, in mechanical failure. Tension accumulation is, therefore, largely dependent on interparticle friction [21] and, more generally, on the flowability of the hydrogen absorbing material. The ability of fine powders to flow is hindered by the action of van der Waals forces, which become dominant as the particle size decreases [22e24].…”

“…The method of the rotating drum allowed us to determine the interparticle friction variation of the hydride forming alloy as a function of activation and hydrogen charge. In a recent work, Charlas et al [21] used rotating drum measurements to calibrate a Discrete Element Modelling (DEM) numerical model that was then applied to calculate strains and stresses in a hydride container subject to cycling.…”

LaNi 5 hydride powder flowability as a function of activation and hydrogen content

“…In these studies, the effect of hydride particle expansion on prototype containers is reported, without studying friction between particles, or between particles and container walls. A recent study of Charlas et al [22] aimed to improve the understanding of the mechanical behavior of hydrides absorbing and desorbing hydrogen uses a Discrete Element Modelling technique to numerically match experimental measurements of a TiVCr BCC alloy. Rotating drum measurements are introduced, obtaining repose angles about twice the angles presented in this publication, possibly because of the use of different gaseous medium.…”