The Discrete Element Method Simulation Of Multi-spot Discharge Of Cement Clinker

Cement clinker is an intermediate product of cement industrial production. By silos the storing and transferring of cement clinker are processed. As a kind of special structure, the silo, the stored materials of which are mainly of granular material property, has a different way of designing and calculating from other ordinary structures. The key to silo structure designing is the appropriate determination of its operating loading, namely the lateral stored material pressure. At present, the calculations of the structure design loading of silos in most countries are based on the Janssen Theory. This theory has been confirmed to have good calculations, which match the real values well in terms of calculating static stored material pressures and can reflect the strained conditions of silos with statically stored material. However, the solution to dynamic stored material pressure calculating by this theory is oversimplified, the way that the static pressures are multiplied by a correction coefficient as calculations of dynamic ones is purely an empirical approach, and can not reflect the real behavior of dynamic interaction. The differences between the calculations and the real values can be very large.The latest development of the discrete element method (DEM) provides a wide and in-depth application in the area of particle (granular material) engineering. The simulation of discharge of silo is one of the applications. Using the DEM can simulate the interaction of stored material and silo when filling, storing and discharging. The DEM is theoretically based on discontinuum, which is a big breakthrough, when other theories treat granular material as continuum, and can reflect the reality better and derive results of better accuracy. Using the DEM can also simulate the flow regime and the strained condition inside the silo, and can provide reference for research of flow of stored material in the silo.In the dissertation, a DEM-based program SISOLV-2 is developed. This program has powerful preprocessor and postprocessor, can simulate the processes of filling material and the discharging of a silo. The calculation results include the state of motion of particles, the velocity field, the pressure field and the principal stress field.The DEM-based program SISOLV-2 is manipulated to simulate the multi-spot discharge of cement clinker, and some useful conclusions are obtained.