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Experimental and numerical study of wall layer development in a tribocharged fluidized bed

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Pages (from-to)860-884
Number of pages25
JournalJournal of Fluid Mechanics
Volume849
DOIs
Publication statusPublished - 25 Aug 2018
Publication typeA1 Journal article-refereed

Abstract

The effects of triboelectricity in a small-scale fluidized bed of polyethylene particles were investigated by imaging the particle layer in the vicinity of the column wall and by measuring the pressure drop across the bed. The average charge on the particles was altered by changing the relative humidity of the gas. A triboelectric charging model coupled with a computational fluid dynamics-discrete element method (CFD-DEM) model was utilized to simulate gas-particle flow in the bed. The electrostatic forces were evaluated based on a particle-particle particle-mesh method, accounting for the surface charge on the insulating walls. It was found that simulations with fixed and uniform charge distribution among the particles capture remarkably well both the agglomeration of the particles on the wall and the associated decrease in the pressure drop across the bed. With a dynamic tribocharging model, the charging rate had to be accelerated to render the computations affordable. Such simulations with an artificial acceleration significantly over-predict charge segregation and the wall becomes rapidly sheeted with a single layer of strongly charged particles.

Keywords

  • fluidized beds, multiphase and particle-laden flows

Publication forum classification

Field of science, Statistics Finland

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