Direct numerical simulation study of end effects and D/d ratio on mass transfer in packed beds

Shivkumar Bale*, Shashank Tiwari, Mayur Sathe, Abdallah S. Berrouk, Krishnaswamy Nandakumar, Jyeshtharaj Joshi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Direct Numerical Simulation (DNS) was performed to investigate the end effects on mass transfer in a packed bed for Reynolds number (Re) ≤ 100. The system considered in this study was naphthalene-air with a Schmidt number (Sc) ∼ 2.52. The location of the spheres’ centers in a randomly packed bed were obtained from Discrete Element Method – Computational Fluid Dynamics (DEM-CFD) simulations. The influence of the confining wall on how packed bed ends affect mass transfer was studied by examining the axial void fraction profile with varying ratio of the column diameter to the particle sphere diameter (D/d). Overall, it was found that the confining wall has a significant impact. The ‘local’ mass transfer coefficient was calculated based on the obtained DNS results and the probability distribution curve and the spatial distribution of the computed ‘local’ Sherwood numbers as function of the ratio X/L (ratio of the height of the active part of the bed to the total height of the bed) were developed to quantify the end effects on mass transfer within packed beds. For a packed bed with no wall effects (D/d = 11), it was found that the end effects can be eliminated by replacing the active particles located at ∼2 sphere diameters from the entrance and ∼1 sphere diameter from the exit by inert particles.

Original languageEnglish
Pages (from-to)234-244
Number of pages11
JournalInternational Journal of Heat and Mass Transfer
Volume127
DOIs
StatePublished - Dec 2018
Externally publishedYes

Keywords

  • Direct numerical simulation (DNS)
  • End effects
  • Mass transfer
  • Packed bed

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