Filling of a grain silo. Part 1: Investigation of fine material distribution in a small scale centre-filled silo

When a silo is being filled with the granular material containing a range of particle sizes, larger particles tend to flow towards the silo wall while the smaller particles accumulate near the centre of the silo. Shelled corn was used in this study. This work encompasses the first part, where the distribution of broken corn and foreign material (BCFM) was investigated in a small scale silo filled from a central filling point (CFP). Factors that were varied included initial BCFM, volume flow rate of material and fill pipe diameter. A new approach was developed to ensure accurate sampling in the radial and vertical direction in the silo. The results indicated that the distribution of fine material became more uniform at lower grain depths and for increasing initial BCFM, volume flow rate and fill pipe diameter. The accumulation of fine material at the centre of the silo increased with increase in the distance from the bottom of the silo. In addition, a nonlinear model was developed to predict BCFM distribution in CFP method. Based on statistical parameters, namely, coefficient of determination (R2), Chi-square (χ2), RMSE (root mean square error) and MRDM (mean relative deviation modulus), the model fit the experimental data reasonably well.