2012 Volume 52 Issue 10 Pages 1785-1793
The formation and the growth of void (crack) in the sintering bed have not been explored. In this study the motions of particles and the air in the nearly actual scale sintering bed were simulated to elucidate the void formation and the growth mechanisms to large scale crack by the simultaneous calculation of Navier-Stokes equations and the Lagrangian DEM equations based on the simple sintering model in which the phase change of particles, the cohesion force due to the liquid film between particles and the fixation process above the melting zone were considered. The air flow among particles facilitated to grow the crack and finally to produce the large scale crack. The cohesion force by the liquid film caused the agglomeration among particles and grew the voids in the melting zone. In the fixation zone the large cohesive force which was 10 or 30 times larger than that in the melting zone in this study advanced the agglomeration and grew the void. Therefore the cohesion force between particles mainly affects the occurrence of the large scale crack. The decrease of mobility of particle motion by the fixation process in the fixation zone generated the locally large contact force which was about 250 times larger than the usual cohesion force between particles in the agglomerate and the large velocity difference between agglomerates. They broke down the agglomerate particle. Through the fixation zone the cracks (voids) further grew and merged to a large scale crack.