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

Petteri Sippola, Jari Kolehmainen, Ali Ozel, Xiaoyu Liu, Pentti Saarenrinne, Sankaran Sundaresan

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)860-884
Number of pages25
JournalJournal of Fluid Mechanics
Volume849
DOIs
StatePublished - Aug 25 2018

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • fluidized beds
  • multiphase and particle-laden flows

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