Abstract: In order to find out the dynamic structural catastrophe of chaotic flow in the vertical upward flow of Kenics static mixer (KSM), the dynamic structure exponents of pressure fluctuation signals in different segments at both left and right sides of the catastrophe points were analyzed based on dynamic exponent segmentation algorithm in turbulent regime with Re=1756~3512. The dynamic structural exponents were discussed under different flow rates and the largest statistic value of dynamic structure exponents Tmax was used to quantitatively characterize the catastrophe features of the complex flow in the KSM. The results showed that Tmean of pressure fluctuation signals increased with increasing of Re for Re≤2107. Because the tube wall strengthened the restrictive function for fluid turbulence, the dynamic structure differences of the fluid tended to become stable for Re≥2458. The effect of radial secondary flow on the complexity of dynamic structural difference in the vortex center was 2~3 times than that near the wall. The dynamic structure produced by axial cutting split-flow was 8~10 times than that by displacement mixing action. The method of pressure fluctuation signals dynamic exponent could well explore instantaneous catastrophe structure of the flow in KSM.

Key words: Kenics static mixer, instantaneous pressure, chaos and catastrophe theory, ynamic exponent segmentation algorithm

摘要： 为更好地揭示旋流静态混合器内竖直上升螺旋流中混沌动力结构突变规律，在湍流状态下(Re=1756~3512)，基于动力指数分割算法，分析了混合器内不同区域的压力脉动时间序列在结构突变点左右两部分的动力学结构指数分布，研究了流量变化对压力波动时间序列的混沌动力学结构指数的影响，并利用动力学指数的最大统计值Tmax定量表征旋流静态混合器内复杂流动的混沌突变特性. 结果表明，当Re≤2107时，静态混合器压力波动信号的平均突变统计指数随Re增加而增大；当Re≥2458时，管壁尺寸对流体湍动约束增强使流体动力结构差异趋于稳定. 径向二次流使漩涡中心处的动力结构差异复杂程度是壁面处的2~3倍；轴向切割分流作用产生的动力结构是移位混合作用的8~10倍. 瞬态压力波动信号的动力学指数模型能较好地挖掘旋流静态混合器内流场瞬时突变结构.

关键词: 静态混合器, 瞬态压力, 混沌突变理论, 动力学指数分割算法