A hydride model for solid and liquid cerium ejecta particles

Abstract

Cerium ejecta particles form after a shock wave impacts a cerium plate with a rough surface or prescribed surface perturbation. When these particles are ejected into hydrogen or deuterium gas the material reacts exothermically and raises the temperature of the particle. Two models are developed to capture the heat and mass transfer that occurs during this process. One model assumes that for larger solid ejecta particles, the loss of mass is negligible while for smaller liquid ejecta particles, the loss of mass during reaction is accounted for. The loss of mass is assumed to occur from the hydride layer being extremely brittle and the fact that it will be relatively easy for the hydride material on the outside of the particle to go into tension, crack and flake off. The model is tested by performing simulations similar to the original experiments that motivated the development of these models and comparing the particle temperatures. While the model is able to capture some general features of the flowfield, inaccuracies clearly exist that must be addressed and the results underscore the need for more isolated experiments where fewer assumptions and physical processes are present simultaneously.