THE INFLUENCE OF STATIC ARCHES ON THE EFFICIENCY OF TECHNOLOGICAL PROCESSES IN A HOPPER

Abstract

Objectives. In practice, the process of loose material flowing from hoppers in different technological processes is often disrupted, resulting in reduced processing efficiency of contained loose materials. One of the most common reasons for the interruption of flows is the formation of dynamic arches in the hopper. From this perspective, the aim of the study is to assess the effect of static arches on the efficiency of technological processes in the hopper.Methods. The study was based on a system of differential equations describing the stationary and equilibrium state of the loose medium, which is integrated in the boundary conditions corresponding to round silos and hoppers. In this case, the analytical expressions for the pressure components of loose material in different directions are derived.Results. The obtained solutions are checked for logical consistency and illustrated with the help of graphs constructed in the area of symbolic mathematics for modeled and real parameters of silos and hoppers. The results of mathematical modeling are compared with experimental data for typical silos. The scatter of the experimental values is related to the processes of compacting the loose material, the time of its storage in the silo, as well as the microvibrational directions of a seismic or technogenic nature. The loose material in the silo resides in an intermediate position between stationary and equilibrium states at all times. The parameters of the loose material (bulk density, external and internal friction angles) represent some generalised values that do not correspond to a specific loose material, which, in addition, can vary over time.Conclusion. It is confirmed that arches formed in the hopper during the static state acquire a dynamic character during material flow, hampering the flow process and consequently reducing the efficiency of the hoppers.

Keywords

• pressure
• loose material
• hopper bottom and walls
• static and dynamic arches
• loose material flow