颗粒介质固-流态转变的理论分析及实验研究

发布时间：2018-05-17 19:28

本文选题：颗粒介质 + 热力学　；参考：《力学学报》2016年01期

【摘要】：颗粒介质由大量离散的颗粒聚集而成,因而与传统固体和流体不同,运动过程中的颗粒介质中可能同时存在多种流态及其相互间复杂的转换过程.颗粒介质弹性失稳机理、不可恢复应变量化是研究颗粒介质固态和流态及固-流态转变的关键.在前期建立的双颗粒温度热力学(two-granular-temperature,TGT)理论基础上,确定了颗粒介质的弹性稳定性条件,建立了不可恢复应变流动法则,搭建了描述颗粒固态-液态及其相互转化的简单模型.颗粒堆积体坍塌过程是典型的颗粒介质固态和流态及其转变过程,因此本文首先开展了25 167个陶颗粒堆积体坍塌过程的实验研究,并使用基于TGT理论的物质点方法和离散元方法对物理实验进行了模拟.结果表明,模型数值结果与物理实验在颗粒堆坍塌过程中的形态、速度分布等细节上吻合很好,同时也发现了现阶段所使用的物质点方法和TGT理论的不足.初步说明TGT理论可以实现颗粒介质固态和流态,以及状态转变的描述.
[Abstract]:Particle media is composed of a large number of discrete particles, so different from the traditional solid and fluid, there may be a variety of flow states and their complex transformation processes in the moving granular media at the same time. The mechanism of elastic instability of granular media and the quantization of unrecoverable strain are the key to the study of solid-state and fluid-state and solid-flow transition of granular media. Based on the two-particle thermodynamics two-granular-temperatureTGTtheory, the elastic stability conditions of granular media are determined, the unrecoverable strain flow rule is established, and a simple model describing solid-liquid particles and their mutual transformation is established. The collapse process of granular deposits is a typical solid state and flow state of granular media and its transformation process. Therefore, the experimental study on the collapse process of 25167 ceramic aggregates has been carried out in this paper. The material point method and discrete element method based on TGT theory are used to simulate the physical experiment. The results show that the numerical results of the model are in good agreement with the physical experiments in the details of the shape and velocity distribution in the process of particle collapse. At the same time, the deficiencies of the material point method and the TGT theory used at the present stage are also found. It is shown that TGT theory can be used to describe the solid state, flow state and state transition of granular media.
【作者单位】：清华大学水沙科学与水利水电工程国家重点实验室;中国科学院水利部成都山地灾害与环境研究所;
【基金】：国家自然科学基金项目(11272048,51239006) 欧盟Marie Curie国际项目(IRSES-294976) 美国全球创新计划(Global Innovation Initiative) 清华大学自主科研计划资助
【分类号】：O347.7

【共引文献】