| Particulate matter system refers to the discrete system formed by the interaction of particles with a diameter larger than 1 micron.It is an important matter form which coexists with fluid and solid in nature.The application fields of particulate matter involve not only construction,industry,medicine and other fields,and natural disasters,such as dust storms,mudslides,and avalanches,are also closely related to the movement of particulate matter.Therefore,the study of particulate matter has important economic value,and scientific significance.Under the combined action of external forces and internal forces,particulate matter will exhibit fluid-like properties,moreover,size segregation occurs during the process.The particle segregation problem was first reported by Brown and received attention from the engineering community.In 1987,it was introduced into the field of physics by Rosato.This problem was named ―Brazil Nut Effect‖.Previous researches on particle segregation were mostly concentrated in intrusion systems and binary mixing systems.The segregation problem in multi-component mixtures has not been extensively studied.The segregation mechanism and factors affecting segregation still need to be studied.In addition,in the past,the study of particle segregation behavior mostly used spherical particles,ignoring the influence of particle shape on the segregation process.In practical issue,the shape of particulate matter varies greatly,and the existed have shown that the shape of particles has a significant effect on sorting behavior.Therefore,this dissertation systematically studies the motion behavior of the ternary hybrid system with spherical and non-spherical particles in vibration and the factors that affect the segregation of the system.Research results show that:(1)Under the same conditions,the ternary system does not eventually form a distinct segregation structure like the binary system,but forms a segregation structure in which small particles are deposited on the bottom and larger particles are mixed on the upper part of the granules;(2)The ternary system has convection during the vibration segregation process,and convection is the reason for the system’s mixing.The system is finally in part of the segregation structure because the mixing mechanism(convection)and the segregation mechanism(leakage)reach a balance;(3)The addition of medium particles has an inhibitory effect on the segregation of the binary system,and the effect of system segregatiob is greatly affected by the parameters of the medium particles.The larger the particle size is,the worse the segregation effect is.There is a critical value of the mass fraction when the value is less than critical value,the system mixture entropy increases with the increase of the mass fraction,and when the value is greater than a critical value,the system entropy of mixture remains unchanged;(4)By comparing the vibrational processes of spherical and capsular particles,it was found that the segregation effect of spherical granules was better than that of capsular granules.The movement of large granules and spherical granules was more active than that of small granules and capsular granules.The study of the variation of force and kinetic energy shows that the force,moment and kinetic energy between large-sized particles and spherical particles are larger than those of small-sized particles and capsule particles,which explains the result from the perspective of force and energy. |
