Introduction. Improving the performance, increasing productivity, reducing the metal consumption of grinding equipment and other mining machines is usually a very expensive process. It requires a large amount of development work, the production of prototype machines, and a large amount of experimental research. In this regard, one of the most important tasks is to simulate the movement of bulk material in operations for processing minerals in various equipment. In such modeling, the discrete element method (DEM) is widely used. The purpose of the research is to compare the models of the movement of the crushed material in the body of a vertical centrifugal mill. Research methodology The motion of the bulk medium in a vertical centrifugal mill was modeled using two models. In the first model, the cylindrical body of the centrifugal mill was assumed to be stationary, and on its surface and on the entire surface of the rotor, conditions were set for the absence of a relative speed of movement of the crushed material. In the second model, a hydrodynamic model was used to describe the motion of a granular material as a viscous incompressible liquid with a compression ratio that depends on the pres-sure. In this model, the viscosity coefficient is represented as consisting of two terms: a constant (analogous to dynamic viscosity) and an excess pressure over hydrostatic pressure. Research results It is established that both models give the same character of the movement of the material in the mill body. It is determined that the absolute velocity of the material movement near the walls and near the mill rotor is approximately the same for both models, but in the data obtained using the hydrodynamic model, as the material moves away from the walls and the rotor, it slows down more than for the model using the discrete element method. It is revealed that the absolute velocity of the material movement near the walls and at the axis of the mill rotor is approximately the same for both models, but in the data obtained using the hydrodynamic model, as it moves away from the walls and the rotor, the material slows down significantly more than for the model using the discrete element method. Based on the simulation results, it can be concluded that for a more accurate simulation of the processes occurring during the rapid movement of bulk material in the grinding equipment, it is preferable to use a model using the discrete element method. It is advisable to use the hydrodynamic model for conducting a large number of search dawns or as a predicate model that will allow you to quickly set the initial velocity values for particles in a model using the discrete element method. Conclusions 1. A hydrodynamic model of the motion of a bulk medium in a vertical centrifugal mill, represented as a viscous incompressible liquid with a compression coefficient depending on the pressure has been developed. 2. It is established that for a more correct simulation of the processes occurring during the rapid movement of bulk material in the grinding equipment, it is preferable to use a model using the discrete element method. At the same time, it is advisable to use the hydrodynamic model for conducting a large number of search calculations or as a predicate model that will allow you to quickly set the initial velocity values for particles in a model using the discrete element method.
Semi-Autogenous Wet Grinding Modeling With CFD-DEM