Computational fluid dynamic simulations of regular bubble patterns in pulsed fluidized beds using a two‐fluid model

Abstract

This simulation study explores the two-fluid model's (TFM) capability to reproduce the alternating bubble patterns in a sinusoidal pulsed fluidized bed (PFB). Simulations were performed with frictional limits ranging between 0.58-0.62 with the inlet gas frequency being varied in the range of 3-6 Hz. The preliminary investigations showed that the Johnson and Jackson frictional model with a frictional limit of 0.61 yields a regular bubble pattern. The inference of this regular bubble pattern was based on the discrete Fourier analysis of the temporal pressure signals obtained at different spatial locations inside the PFB. Although the one-dimensional temporal pressure signals character-Zhizhong Ding and Shashank S. Tiwari have contributed equally.

On the role of energy dissipation in a dynamically structured fluidized bed

“…3D simulations seemed to provide a more reproducible (yet unstable) set of nucleation sites, but the arrangement obtained did not represent the triangular lattice observed experimentally. More recently, Ding et al demonstrated that a 2D TFM, coupling a tuned frictional stress model, could reproduce some eposides of bubble alternation, although the structures formed often collapsed and could not be sustained over time (Ding et al, 2021). It is noteworthy that self-organization in deep beds is only observed experimentally when the bed operates under very dense conditions and oscillates across the minimum fluidization conditions, where the flow transitions between inertial and quasistatic regimes.…”

Segregation and intermixing in polydisperse liquid–solid fluidized beds: A multifluid model validation study

“…Comparison of the axial solid hold‐up profiles predicted from CFD against experimental results of Galvin et al 27 for a binary particle mixture. CFD, computational fluid dynamics.…”

“…The standard k‐ε model has five empirical constants C μ , C ε 1 , C ε 2 , σ k , and σ ε in its formulation and their values are 0.09, 1.44, 1.92, 1.0, and 1.3, respectively. These standard values resolve the flow field in fluidized beds 6,26,27 and have been used in the present work.…”

Hydrodynamic Predictions of the Ultralight Particle Dispersions in a Bubbling Fluidized Bed

“…Thus, it is reasonable to involve the frictional energy dissipation term to improve the translational energy term of particle. Numerous studies have been reported using kinetic theory of granular flow bubbling fluidized bed based on the isotropic granular temperature hypothesis [50][51][52][53][54][55][56][57]. Lu et al (2009, 2010) [58,59] considered that the isotropic behavior of granular temperature mainly comes from the particle-particle collisions and anisotropic granular temperature is significantly dominated by particle motion that is a function of local particle velocity and effects of surrounding transport momentum particle-fluid system.…”