Analyzing the Power-law Decay of Power Spectrum Intensity and Bevavior of Intermittent Chaos of Pressure Fluctuations in a Gas-Solid Fluidized Bed
气-固流化床压力波动功率谱指数衰减与阵发性混沌行为探讨

Pressure fluctuations in a gassolid fluidized bed (0.09 m in diameter and 1m in height) with polyethylene particles were analyzed using both mutual information theory and the power-law decay of power spectrum intensity. Intermittent chaos has been experimentally observed mainly in hydrodynamic systems. Intermittency means the occurrence of a signal that alternates randomly between long regular phases (the so-called laminar) and relatively short irregular bursts (the so-called intermittency). The route of intermittent burst to chaos with the increase of gas velocity in gassolid fluidized bed was verified quantitatively according to the power-law decay of power spectrum intensity: S(f)f -a. This research shows that the laminar interval length of pressure fluctuation shortens gradually and the chaos bursts more and more frequently till to pure chaos with increase of gas velocity. By studying the relationship between the laminar interval length and Reynolds number, it is shown that the average laminar interval length decays with the power-law: T(Re-Remf)-0.492 and the route to chaos of fluidization dynamics presents the mechanism of type I intermittency.