摘要
根据功率谱低频发散与阵发性混沌本质之间的联系,通过分析压力波动信号的功率谱指数衰减,并结合互信息函数分析,证实了流态化动力学所具有的阵发性混沌特性. 研究表明,随气速增加,压力波动层流区时间长度逐渐缩短,混沌越来越频繁地阵发,最终通向完全混沌状态. 此外,研究了层流区时间长度与雷诺数之间的关系,表明层流区时间长度随气速增加呈指数衰减,流态化动力学呈现出I型阵发机制.
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.
出处
《过程工程学报》
CAS
CSCD
北大核心
2002年第2期101-106,共6页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(编号:29676026)
关键词
气-固流化床
压力波动
功率谱指数衰减
阵发性混沌
层流区时间长率
雷诺数
pressure fluctuation
the power-law decay of power spectrum
intermittent chaos
the laminar interval length
Reynolds number
