Segregation Study And Application Of Granular Mixture Under Horizontal Pendulum Vibrations

Granular matte is a special material form, which is different from the solid and fluid in nature. Because of the discrete characteristics and the nonlinear dissipative characteristics of the solid particles in granular system, granular matter can exhibits much more mechanical properties than the ordinary solid and fluid. Especially under the external dynamic excitation, granular matter shows complex physical behaviors,such as convective motion, mixing, size separation, and segregation. And the study on the mechanical properties of granular matter has become one of the hot issues in the current scientific field. Closely associated with production and living of human being,the mechanical properties of granular matter have been widely used in the preparation,mixing, sorting, storage and transportation process of industrial and agricultural particles, and granular matter has a certain relationship with dust storm, debris flow,avalanche and other natural disasters. Therefore, the study on the granular matter has an important scientific significance and engineering application value.Under the external vibrations, granular mixture system exhibits the dynamic phenomenon of particle segregation, which reflects the fluid characteristics. Most studies of particle segregation are confined to the vertical vibration modes, while the separation behavior of a monolayer particles is more common investigated in horizontal vibration. Particle segregation with a thick layer under horizontal pendulum vibrations has not been studied and reported. The mechanism of particle segregation and the effects of factors affecting particle segregation need to be further studied in the thick material layer under horizontal pendulum vibrations.The segregation of binary granular matter under horizontal pendulum vibrations has been investigated through numerical simulation using a 3D discrete element method, the segregation mechanism and dynamic behavior of particles are also analyzed at mesoscopic level. The study shows that the particle system mainly exhibits a similar movement pattern of laminar flow or turbulent flow in the horizontal pendulum, and the particle velocity, energy and momentum are periodic fluctuations. Vibration causes the destruction of particle force chain and changes particle gaps continuously. Relying on gravity, heavy particles fill in the bottom gaps,and light particles are squeezed and move to the upper layer, thereby inducing the segregation effect that heavy particles are in the bottom and light particles are in the upper part of material layer. The effects of vibrator geometry structure, density ratio and particle size ratio on granular segregation are discussed by using the Lacey mixing index. Finally, granular segregation test trials(steel and plastic balls, paddyrice and short stalk particles) were designed and conducted under horizontal pendulum vibrations, and the experimental results prove the correctness of simulation results and show that the 3D discrete element method can accurately simulate and predict the dynamic behavior of granular matter.The studies in this paper can provide a useful reference both for the further understanding of particle segregation and the improvement of granular dynamics theory, and also provide a degree of guidance for the particles separation in practical engineering.