Monitoring of liquid sprayed conical spouted beds by recurrence plots

In this study, the chaotic behavior of gas-solid flow in a laboratory scale conical spouted bed during spraying of water on the sugar particles was investigated using non-linear analyses of pressure fluctuations (PFs) and acoustic emission (AE) signals. The phase space trajectories, recurrence plots (RP) and recurrence quantification analyses (RQA), as powerful non-linear techniques, were used for monitoring of the bed hydrodynamics. It was concluded that the reconstructed phase space trajectories of both PFs and AE signals approach to a slim and elongated patterns with the formation of agglomerates due to injection of water into the bed. Examinations of the RP maps show that the contribution of patches with larger distances increases by an increase of water content in the bed. Moreover, the RQA results show that the maximum length of diagonal lines of RPs increases by injection of the water into the bed showing that the hydrodynamic status of the bed becomes more deterministic. The results of this work show the high potential of these methods for proper understanding of the hydrodynamics of spouted beds with liquid injection and associated agglomeration phenomenon.