Pressure distribution of central cone silos during filling and discharge: Multi-scale experimental study

Abstract Central cone silo with high blending efficiency can be a key part of the production process in cement industry. Filling and discharge tests of central cone silos with different aspect ratios are conducted via a multi-scale experimental program to investigate the flow pattern of the stored material and the pressure distribution on the wall and cone. The filling tests imply the wall pressure increases with the depth until the peak value near the cone top position, beyond which both wall pressure and cone pressure decrease with the depth. The sequent discharge tests indicate the same number of inverted conical surfaces as the discharge outlets appear on the top surface of the stored material. The vertices of inverted conical surfaces are directly above the discharge outlets whereas the most significant overpressure of the wall and cone occurs in the far end of the outlet. For higher aspect ratio, the overpressure factors of the wall and cone decrease slightly. The maximum overpressure factors of the wall are close under different discharge modes, while the maximum overpressure factors of the cone are quite different under different discharge modes. The pressure coefficients according to Rankine’s equation and Jaky's equation can accurately predict the pressure on the wall in the upper region and the cone region, respectively. The predicted pressure on the cone by the equations for the hopper pressure in the code ACI 313–16 is obviously overestimated, and it cannot reflect the changing law of the cone pressure decreasing with the increase of the depth.