Pressure fluctuations of a fluidized bed of nanoparticles were measured during the fluidization of nanoparticles with and without a magnetic field at a frequency of 50 Hz. Recurrence quantification analysis (RQA) and wavelet transform were used to determine the frequency range of various flow structures in the bed at three scales. The frequency ranges of the macro-, meso-, and micro-structures were determined to be 0–49 Hz, 49–781 Hz, and 781+ Hz, respectively. Comparison of the determinisms of the sub-signals with and without the external field revealed that in the presence the field, breakage of larger agglomerates occurs faster than re-agglomeration of small agglomerates into larger ones. The power spectral density function of the pressure fluctuations indicated that with an external magnetic field, the power and the frequency range of the pressure signal of macro-structures do not change noticeably. However, the power of the meso-structure signal increases and its frequency range is widened toward higher frequencies, confirming that the number of small bubbles and agglomerates increase in the bed. In addition, the energy of signal analysis indicated that the external field significantly increases the share of meso-structures in the bed, confirming the RQA results.

在有和没有磁场以50Hz的频率流化纳米颗粒的过程中，测量了纳米颗粒流化床的压力波动。递归量化分析（RQA）和小波变换用于确定三种尺度下床层内各种流动结构的频率范围。宏观，中观和微观结构的频率范围分别确定为0–49 Hz，49–781 Hz和781+ Hz。比较带有或不带有外部场的子信号的确定性，结果表明，在存在场的情况下，较大的团块的破裂比将较小的团块重新团聚为较大的团块要快。压力波动的功率谱密度函数表明，在外部磁场作用下，宏观结构压力信号的功率和频率范围变化不大。但是，介孔结构信号的功率增加，并且其频率范围朝着更高的频率扩展，这证实了床中小气泡和团块的数量增加了。此外，信号分析的能量表明，外部场显着增加了床中细观结构的份额，从而证实了RQA结果。