快速流化床提升管中气固流动行为的非线性分析

对φ100mm×16m、FCC固体颗粒的快速流化床提升管内环-核流动区局部颗粒含量脉动行为进行了非线性分析，用Kolmogorov熵表征了其气固流动行为.结果表明，Kolmogorov熵沿提升管环-核流动区径向有3个显著变化区域，以此为依据将提升管环-核流动区的气固流动行为沿径向分成3个流域：单颗粒随机运动控制的核心流域；单颗粒混沌控制的过渡流域；边壁控制的环形流域.同时，从颗粒对垂直气固流动系统中气固湍动程度影响的角度，解释了Kolmogorov熵的径向分布特征及其与流动结构的关系.

NONLINEAR ANALYSIS OF GAS-SOLID FLOW BEHAVIOR IN FAST FLUIDIZED BED RISER

A fast fluidized bed riser with 16m height and 0.10m ID was operated with FCC particles and in a wide range of operating conditions.The superficial gas velocity U_g ranged from 3.5m•s^-1 to 8.1m•s^-1, and the solids circulating rate G_s was from 50kg•m^-2•s^-1 to 201kg•m^-2•s^-1.Time series signals of solids holdup fluctuation were measured at a frequency of 900Hz using an optical fiber located at 8 axial and 11 radial positions.The nonlinear method was used to analyze the time series and consequently Kolmogorov entropy was calculated to describe the dynamic characteristics of the gas-solid flow behavior in the annular-core section. The results showed that Kolmogorov entropy could describe the annular-core flow structure. According to three marked characteristics of Kolmogorov entropy in the radial direction, three flow regions were identified：random-particles-controlled core region, chaotic-particles-controlled transitional region, wall-controlled annulus region.The change of Kolmogorov entropy in the radial direction was also interpreted based on the influence of solids on gas turbulence structures.