气固两相流化床压力脉动的混沌特性分析

摘要

在自行搭建的冷态流化床实验台的基础上,分别利用 Kolmogorov 熵、关联维以及 Lyapunov指数对气固流化床床内气泡运动的复杂性进行了混沌特性分析,从定性、定量两个方面分析了鼓泡床、节涌床、湍动床和快速流化床的流动特性.结果表明：在流化床风帽入口P0处所测得的压力信号能够传达与侧墙压力测点P1－P10相同的信息；流化床气固两相流动具有混沌特性；鼓泡床压力脉动信号的 Kolmogorov 熵为0．11~0．15,其混沌程度最大,而节涌床、湍动床和快速流化床的Kolmogorov熵分别在0．08~0．09,0．09~0．11和0．11~0．13之间,混沌特性较弱；利用Kolmogorov熵、关联维以及 Lyapunov 指数的理论方法能够很好地辨别流化床的流化状态,有助于理解流化床的流动机理.%On the basis of a self-designed fluidized bed experimental platform,the Kolmogorov entropy,cor-relation dimension and Lyapunov exponent were adopted to carry out chaotic analysis on complexity of bubble movement in gas-solid fluidized bed.The flow characteristics of the bubbling regime,slugging re-gime,turbulent regime and fast fluidized regime were analyzed qualitatively and quantitatively,respective-ly.The results reveal that,the pressure signal detected at the fluidized bed air hood entrance P0 can transfer the same information as that obtained form measuring point P1 to P10 .The bubbling bed's Kolmogorov en-tropy is about 0.11 to 0.15,which has the greatest chaos degree,while the slugging bed,turbulence bed and fast fluidized bed's Kolmogorov entropy is 0.08 to 0.09,0.09 to 0.11,0.11 to 0.13,respectively,which has a relatively weak chaos degree.The Kolmogorov entropy,the correlation dimension and Lyapunov ex-ponent can be well used to distinguish the fluidization states.It has great significance for understanding the mechanism of fluidized bed flow.