Abstract

The vertical roller mill is an important crushing and grading screening device widely used in many industries. Its classification efficiency and the pressure difference determine the entire producing capacity and power consumption, respectively, which makes them the two key indicators describing the mill performance. Based on the DPM (Discrete Phase Model) and continuous phase coupling model, the flow field characteristics in the vertical roller mill including the velocity and pressure fields and the discrete phase distributions had been analyzed. The influence of blade parameters like the shape, number, and rotating speed on the flow field and classification performance had also been comprehensively explored. The numerical simulations showed that there are vortices in many zones in the mill and the blades are of great significance to the mill performance. The blade IV not only results in high classification efficiency but also reduces effectively the pressure difference in the separator and also the whole machine. The conclusions of the flow field analysis and the blade effects on the classification efficiency and the pressure difference could guide designing and optimizing the equipment structure and the milling process, which is of great importance to obtain better overall performance of the vertical roller mill.

Highlights

  • Speaking, the literation study shows the research on the vertical roller mill like the powder separation mechanisms, and the flow characteristics are still incomplete and not comprehensive. e blades especially, as key parts in the roller mill, have not been comprehensively investigated

  • It can be obtained that there is an obvious vortex phenomenon between the wind ring and the grinding roller, and this phenomenon is consistent with what Wang [9] and Sun [10] described. e appearance of the vortex will make the particles fully contact with the air, which is conducive to the full coupling of the particles and the airflow

  • A numerical model focusing on an industryused vertical roller mill has been established based on the CFD method combining the continuous model with Discrete Phase Model (DPM)

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Summary

Model Description

In the numerical calculation of the flow field of the vertical roller mill, in order to ensure the calculation accuracy, the global mesh size of the blade region is set as 0.01, and the number of meshes is 6.17 million With such a number of meshes, the calculation efficiency of the sliding mesh model and the dynamic mesh model is very low, and the numerical simulation work cannot be solved. To ensure the accuracy of the particle size distribution of the flow field simulation, the Figure 4: 3D mesh of vertical roller mill

Results
Flow Field Description
Flow Field and Classification Efficiency Analysis
86.2 Type III
Conclusions
Full Text
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