Multi-scale analysis of flow structures in fluidized beds with immersed tubes--颗粒学报PARTICUOLOGY

Norouzi, H. R., Tahmasebpoor, M., Zarghami, R., & Mostoufi, N. (2015). Multi-scale analysis of flow structures in fluidized beds with immersed tubes. Particuology, 21, 99-106. https://doi.org/10.1016/j.partic.2015.01.005

Multi-scale analysis of flow structures in fluidized beds with immersed tubes

Hamid R. Norouzi ^a, Maryam Tahmasebpoor ^b, Reza Zarghami ^a *, Navid Mostoufi ^a

a Multiphase Systems Research Lab, School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155/4563, Tehran, Iran
b Department of Chemical and Petroleum Engineering, University of Tabriz, P.O. Box 5166616471, Tabriz, Iran

10.1016/j.partic.2015.01.005

Volume 21, August 2015, Pages 99-106

Received 19 December 2013, Revised 30 November 2014, Accepted 22 January 2015, Available online 14 May 2015, Version of Record 6 June 2015.

E-mail: rzarghami@ut.ac.ir

Highlights

• DWT, RP and RQA were used to capture effect of immersed tubes on hydrodynamics of fluidized bed.

• Insertion of tubes affected flow structures more pronounced at low gas velocities.

• The RP of meso-structures was more similar to that of main signal.

• Results showed that bed became less periodic when tubes were inserted.

Abstract

Multi-scale analysis and non-linear analysis were combined to investigate the hydrodynamics of fluidized beds with and without horizontal tubes. Pressure fluctuations were measured and analyzed employing discrete wavelet analysis, recurrence plot analysis, and recurrence quantification analysis. A systematic procedure was followed to determine wavelet parameters. At low gas velocities, the energy of macro-structures reduces with the addition of the first tube and then increases with the addition of a second tube. However, there is no notable difference at high gas velocities. Determinism is high for the bed without tubes, which can be attributed to the periodic behavior of bubbles. Determinism decreases with the addition of tubes because the breakage of bubbles results in less periodic behavior. The three methods of analysis used in this study captured the effects of immersed tubes on the hydrodynamics of fluidized beds. Recurrence quantitative analysis was found to be a powerful and easy-to-use method that can capture the nonlinear characteristics of fluidized beds much more quickly than conventional methods of nonlinear analysis. This method can thus be effectively used for the online monitoring of hydrodynamic changes in fluidized beds.

Graphical abstract

Keywords

Immersed tube; Non-linear analysis; Pressure fluctuations; Recurrence plot; Wavelet transform

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