Mechanism Analysis on Stress Accumulation in Cylindrical Vertical-Placed Metal Hydride Reactor

Abstract

It's known that the pulverization-densification mechanism of metal hydride may cause the stress accumulation in metal hydrides reactors. In this paper, this idea is proved based on granulometry and a new idea of cycling compression effect is presented, which is caused by the friction between wall and metal hydrides. Through theoretical analysis, the cycling compression effects is shown to increase the localized packing rate from top to down in vertical-placed reactors and thus lead to the maximum deformation in the bottom of reactors, proving that it is the interaction of pulverization-densification effect and cycling compression effect resulting in the stress problems of vertical-placed reactors. Further study points that the effective methods relieving the cycling compress effect are to decrease hydrogen absorption/desorption cycle number, slenderness ratio of reactor, wall friction factor and initial packing rate, or to lower the thermal conductivity and the volume expansion coefficient of metal hydrides.

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

“…The first idea is to try to use mechanical laws coming from the modelling of granular media like in soils mechanics or powder mechanics [30]. An attempt has been made by Hu et al [31]. In this model, Hu et al are using a phenomenological Shima and Oyane model.…”