Abstract:

Generally, single-component multiphase systems exhibit three different structures and properties in solid, liquid, and gaseous state with temperature changes. The multiphase system consisting of solid particles and fluids in a circulating fluidized bed also experiences three structures with the increase of gas flow velocity, namely, bubbling, turbulence and rapid flow. Although the two systems are quite different in structure and nature, using the concept of mesoscience to analyze the state of the system, the transitional parameter, the driving force for the system state evolution and the underlying mechanisms, the two systems turn to be quite similar in nature. Their physical roots are alike in all important essentials, which are the inevitable result of the compromise in competition between different dominant mechanisms in the complex systems. After comparing the fluidization and the phase transition, a new proposition based on the energy minimization multi-scale (EMMS) model is suggested to sufficiently characterize the real non-equilibrium kinetics of phase transition.

Key words: phase change, multiphase flow, fluidization, complex system, compete, coordinate

摘要：

通常单组分多相系统随着温度的变化会呈现固态、液态和气态三种不同的结构和性质，而固体颗粒和流体组成的多相系统在循环流化床中随着气体流速的升高也会经历鼓泡、湍动和快速流化三种结构。两类体系虽然呈现不同的结构和性质，但是用介科学的概念对体系状态、区域过渡参数、驱动系统状态演变的能力、体系的控制机制等进行类比和分析，其物理根源却大同小异，均为复杂系统中不同控制机制在竞争中协调的必然结果。在对比了流态化与物质的相变两类体系之后，提出了基于能量最小多尺度模型（EMMS）的思想来构建相变理论的主张，从而期望能够充分理解物质的相变这一非平衡动力学过程。

关键词: 相变, 多相流, 流态化, 复杂系统, 竞争, 协调