Dynamic characteristics of bubbling fluidization through recurrence rate analysis of pressure fluctuations

Pressure fluctuations signals of a lab-scale fluidized bed (15 cm inner diameter and 2 m height) at different superficial gas velocities were measured. Recurrence plot (RP) and recurrence rate (RR), and the simplest variable of recurrence quantification analysis (RQA) were used to analyze the pressure signals. Different patterns observed in RP reflect different dynamic behavior of the system under study. It was also found that the variance of RR   (σRR2) could reveal the peak dominant frequencies (PDF) of different dynamic systems: completely periodic, completely stochastic, Lorenz system, and fluidized bed. The results were compared with power spectral density. Additionally, the diagram of σRR2 provides a new technique for prediction of transition velocity from bubbling to turbulent fluidization regime.

Graphical abstractRecurrence plot of pressure fluctuation signals measured in a fluidized bed.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► RP and RQA are helpful in dynamic characterization of gas-sold fluidized beds. ► Patterns in RP of gas-solid fluidization system reflect dynamic behavior at different time scales. ► RR provides new way to predict transition velocity from bubbling to turbulent fluidization regime.