In this paper, the intrinsic and contact parameters of tomato straw particles were determined. Based on the natural angle of repose of the material, the discrete element simulation method parameters were calibrated by orthogonal test. Based on these parameters, a series of experiments were carried out. It is found that the particles form a macroscopic convective mixing process. The particles of that material form a certain angle in the normal direction of the surface of the blade to do divergent motion, and the farther away from the blade, the smaller the particle velocity. There are many turbulent regions between the upper and lower blades. The particle movement shows the process of spiral ascending and spiral descending, and there is no obvious diffusion movement in the diameter direction. The increase of blade rotation speed, the increase of pitch and the decrease of filling height are beneficial to the improvement of material mixing effect. The high-efficiency mixing mechanism is revealed, which provides a theoretical basis for the later equipment development and optimization.
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