Static pressure distribution characteristics of powders stored in silos

Abstract

Static pressure distribution of the wall is essential to the optimal characteristics and discharge stability of the powder from products (bulk solids) in a silo. A Geocomp Shear Trac-II system was used to measure the flow properties of three different types of material, with an emphasis on the determining the best results in experiments using a special test silo with conical hopper dependent on the static pressure distribution of the silo wall. Experimental results shows that with an increase in height from the outlet, the pressure in a hopper gradually increases, while the silo wall’s normal pressure in the cylinder decreases. The maximum pressure appears at the silo-hopper junction. Three different material types are chosen based on their ability to have a weakening effect on horizontal pressure. With the increase in particle size, the horizontal pressure in the silo junction remained constant. In the cylinder cross section, the larger the particle size, the higher the horizontal pressure. Meanwhile, the vertical pressure distribution shows the opposite trend. With the increase in moisture content, horizontal pressure increases, and the silo wall’s normal pressure decreases. The influence of the moisture content on the vertical pressure of the cone cross section is weak. In the cylinder cross section, the vertical pressure increases with the increase in moisture content. The experimental data created in this study can serve as a reference to guide the design of new silos as well as the maintenance tasks of established silos. This paper can serve as a reference on what silo parts must be reinforced under higher pressure during the unloading process.