Study on the packing characteristics of a special “J” shape ceramic packed pebble bed based on discrete element modeling

Abstract

The packing structures of a special “J” – cylinder-tours shape ceramic packed pebble beds, which might be used in the breeding zone of future fusion blanket and the other applications were numerically studied by the Discrete Element Method. The contact force and force chain distribution and the effect of the pebble diameter on the global packing factor have been investigated. Meanwhile, the analyses of radial and axial local packing factor distribution features and coordination number distribution were performed. The results showed that the global packing factor increased with decreasing pebble diameter and the cylindrical part of the packed pebble bed had a slightly higher global packing factor than the torus part. The contact force kept decreasing after a short period of rising and the force chain distribution showed a clear difference between two parts of the packed pebble bed. Both the radial and axial local packing factor exhibited oscillation behavior but a clear difference observed in two parts. The coordination number distribution was also analyzed to investigate the contact status in the packed pebble bed. The presented results of these investigations added to the understandings of the packing structure of irregular shape packed pebble beds, hence, could provide references for fusion facility design and other areas of industry such as chemical engineering research.