颗粒物质在振动环境中的分离现象及形成机理研究

【作者】 郭长睿；

【导师】 蔡绍洪；

【作者基本信息】 贵州大学 ， 理论物理， 2007， 硕士

【摘要】 对颗粒物质的状态、特性及运动规律的研究是当前物理学前沿领域的一个热点课题。目前人们对颗粒物质运动规律的认识还不够清晰，特别是对振动条件下颗粒物质的运动规律和机理还有待深入地研究。本文主要针对颗粒物质在振动环境下所出现的分离现象，运用平均场理论思想和统计力学方法，借助与数值计算手段来分析和研究振动颗粒体的运动变化趋势及分布规律，以探求颗粒物质振动分离现象的形成机理。Edwards，M．Tarzia等人所构建的颗粒振动分离模型成功地解释了垂直振动的颗粒分离现象，但无法解释水平振动的颗粒分离现象。本文在Edwards，M．Tarzia模型的基础上构建了一个更为普适的含广义势的颗粒振动分离模型，不仅能将E-M模型包含在内，解释垂直振动的颗粒分离现象，也成功地解释了水平振动颗粒分离现象。本模型还可以进一步推广来解释含其他势的颗粒振动分离现象。本文用该模型计算了2种不同大小颗粒组成的水平振动体系，结果表明在振动的过程中，大颗粒占据系统中心格点的概率较大，大颗粒有向盘中心聚集的趋势。随着振动的持续进行，大颗粒在盘中央分布的密度加大，最终导致大颗粒在中心聚集的分离现象。本文的研究结果表明：颗粒物质分离现象是由系统所受到外界的振动力和其所处的某一势场(力场)共同作用下形成的。这在一定程度上揭示了颗粒物质出现振动分离现象的物理机制。本文主要有以下创新之处：(1)建立了一个含广义势的颗粒振动模型，比E-M模型更具普适性。(2)首次计算了水平振动状态下的颗粒分布趋势，在一定程度上解释了水平振动体系的颗粒分离现象。(3)首次提出颗粒系统振动分离现象是由系统所受的振动与其所处的势场共同作用所导致。通过本文的研究分析，能够对颗粒物质的运动特性有进一步的理解，对颗粒物质振动分离机理有更加深刻的认识。这对食品工业、化学工业中分离大小、质量不同的颗粒；通过管道运输颗粒等工业技术有理论上的指导意义。更多还原

【Abstract】 Much attention of physicists have been devoted to granular materials in the recent years. However, there are still many phenomena appearing in granular matters cannot be explained completely. Especially also remain to study to movement law and mechanism of the granular materials under the vibration condition deeply. This thesis is directed primarily to separation phenomena appeared under the environment of vibration of granular materials, use the mean field theory thought and statistical mechanics method, through calculating with number value the means analyzes and studies the movement tendency of the granular materials and distributes the law, in order to the formation mechanism of seeking the vibration of granular materials and size segregation. Edwards, M.Tarzia,et al. constructed vibration separate model succeed in explain vertical vibrant granular segregation, but unable to explain horizontal vibrant granular segregation. This thesis based on Edwards, M.Tarzia’s models for general vertical vibration of particle including generalized potential at the foundation of model, included E-M not merely, explain vertical vibrant particle separate the phenomenon, have explained the phenomenon of horizontal vibration granular segregation successfully too. This model can also be further popularized to explain that separate the phenomenon in vibration of particle including other potential. This thesis uses this method to calculate the horizontal vibration system that the granule of 2 kinds of different size makes up. The result shows: in the course of vibration, the big particle will assemble to centre of the plate , The large particle probability of occupying the lattice of centre is large. Granular segregation to receive because of system external vibration force and received by it a certain potential field cause act on together. This has announced the granular materials appears in the physical mechanism of separating phenomenon of vibration in a certain extent.This thesis mainly has the following innovation: (1)Have set up a particle vibration model including generalized potential, general and right even more than E-M model. (2)Calculate horizontal vibration particle of state distribute trend, explain horizontal vibration particle of system separate the phenomenon to a certain extent for the first time.(3) Propose granular segregation to act on, lead to the fact together because of vibration and potential field system receive for the first time.Research and analyse through being herein, can have further understanding to the movement characteristic of the granular materials, there is deeper understanding to segregation and mechanism to the vibration of granular materials. To this Industrial technology of separating different particles in food industry, chemical industry and transporting granular materials through the pipeline has directive significance in theory.更多还原