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由于循环流化床气-固两相流动规律相当复杂,使得至今对其流动规律的认知仍不足以直接用于循环流化床的工业设计与放大。近十多年中,确定性混沌理论已被用于循环流化床动力学特性的研究,与其密切相关的分形理论也被用于流化床流动特性的研究。然而,这些研究所用均是采用单分形理论,而单分形理论对解释循环流化床复杂的非线性气-固流动行为显得能力不足。为了探讨循环流化床内颗粒流体系统非线性、非均匀性和混沌特性机理,本文引入不同测度多重分形分析的方法,用小波变换模极大值与多重分形测度分析方法相结合,检测循环流化床颗粒浓度波动信号奇异性并得出多重分形奇异谱。结果表明循环流化床颗粒浓度波动信号具有明显的多重分形特性,小波变换多重分形方法可以用来描述床内颗粒流动特性,为探讨循环流化床颗粒流体系统非均匀机制提出了一种新的方法。
Due to the complexity of gas-solid two phase flow in circulating fluidized bed, the cognition of its flow law so far is not enough for direct industrial design and amplification of circulating fluidized bed. In recent ten years, the deterministic chaos theory has been used to study the dynamic characteristics of circulating fluidized bed. The fractal theory closely related to it has also been used to study the fluidized bed flow characteristics. However, the single fractal theory is used in these studies, while the single fractal theory is not enough to explain the complex nonlinear gas-solid flow behavior of a circulating fluidized bed. In order to investigate the nonlinear, inhomogeneous and chaotic mechanism of particle fluid system in CFB, this paper introduces the method of multifractal analysis with different measures, and combines the method of wavelet transform modulus maxima and multifractal measure analysis to detect the circulation flow The singularity of the fluctuating signal of the bed particle concentration and the multifractal singularity spectrum are obtained. The results show that the circulating fluidized bed particle concentration fluctuation signal has obvious multifractal characteristics. The wavelet transform multifractal method can be used to describe the particle flow characteristics in the bed. In order to discuss the nonuniform mechanism of the circulating fluidized bed particle fluid system, a new method.