Characteristics of Chaotic Dynamic Structure Catastrophe of Instantaneous Pressure Signals in a Kenics Static Mixer

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 T max was used to quantitatively characterize the catastrophe features of the complex flow in the KSM. The results showed that T mean of pressure fluctuation signals increased with increasing of Re for Re≤2 107. Because the tube wall strengthened the restrictive function for fluid turbulence, the dynamic structure differences of the fluid tended to become stable for Re≥2 458. 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.