Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Analysis and Modelling of Concentration Waves in Liquid - Solid Fluidized Beds in the Linear Regime
Submission Author:
Victor Shumyatsky , DF , Brazil
Co-Authors:
Victor Shumyatsky, Yuri Dumaresq Sobral, Francisco Ricardo Cunha
Presenter: Victor Shumyatsky
doi://10.26678/ABCM.COBEM2021.COB2021-1612
Abstract
In this work, we investigate one-dimensional instabilities that occur in fluidized beds, focusing mainly on liquid-solid beds. The full set of averaged equations of motion for the continuous phases is used, as well as closure relations for the stress tensors of the fluid and solid phases and the interaction force between the phases. A linear stability analysis in the wavenumber space is performed in order to obtain the dispersion relation and the growth rate of small disturbances to the state of homogeneous fluidization. The influence of the physical parameters of the system, such as the Froude and Reynolds numbers, the density ratio between the phases on the stability of the bed is investigated. The effect of the particle pressure and particle viscosity on the bed stability is also examined. The results of this analysis are presented in terms of wave temporal growth rate and wave velocity as a function of wavenumber. In this way, the variation of one parameter while maintaining all other parameters fixed permits us to understand what physical mechanisms create instabilities in fluidized beds. In particular, we show the stabilizing effect that particle pressure and viscosity have on a fluidized bed and that high Froude number beds, despite having a narrow region of unstable modes, have large growth rates for high wavelength disturbances.
Keywords
Fluidized Beds, Linear stability, Concentration waves
