The size segregation and voidage distribution down a green bed formed on an iron ore sinter strand were investigated experimentally and using Discrete Element Method (DEM). The simulated and experimental results showed that an increase in feed rate (from 6 kg/s/m to 18 kg/s/m) significantly decreased the level of vertical size segregation and the granule packing voidage of each bed sub-layer. With the increase in rill plate angle (from 45 to 65), the level of vertical size segregation first decreased and, then, remained relatively constant. Furthermore, the results indicated that the voidage of each bed sub-layer generally increased with the increase in lambda. In conclusion, enhancing the vertical size segregation down the green bed can generally improve the voidage of the green bed and thus increase the bed permeability. (C) 2019 Elsevier B.V. All rights reserved.