Imbalanced descending behavior of solids in a blast furnace was studied using a three dimensional model furnace, considering the circumferential imbalance of the coke consumption at the raceway zone and the inner surface profile of the furnace wall. Results are summarized as follows ;
1) In case that there were some closed tuyeres or the local wall scab at the middle part of the shaft in blast furnace, it was found that the descending velocity above them became larger than that at the other part at the throat.
2) The erosion of the furnace wall only at the upper part of the shaft (h/D<0.4) increased the descending velocity at the throat above the eroded part, where h is the distance from the top of the shaft and D is the diameter of the throat.
3) The peripheral dead zone was formed just above the closed tuyeres, of which geometry was different from that of the central dead zone. Stress analysis made it clear that the stress field in the lower part had the relation of σθ<σv<σh and the shape of the peripheral dead zone was determined by σθ and σv where σv, is the vertical stres, σh is the horizontal stress and σθ is the circumferential stress.
