Turbulent Bubble-Laden Channel Flow of Power-Law Fluids: A Direct Numerical Simulation Study

Felix Bräuer, Elias Trautner*, Josef Hasslberger, Paolo Cifani, Markus Klein

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Downloads (Pure)

Abstract

The influence of non-Newtonian fluid behavior on the flow statistics of turbulent bubble-laden downflow in a vertical channel is investigated. A Direct Numerical Simulation (DNS) study is conducted for power-law fluids with power-law indexes of 0.7 (shear-thinning), 1 (Newtonian) and 1.3 (shear-thickening) in the liquid phase at a gas volume fraction of 6%. The flow is driven downward by a constant volumetric flow rate corresponding to a friction Reynolds number of Reτ≈127.3. The Eötvös number is varied between Eo=0.3125 and Eo=3.75 in order to investigate the influence of quasi-spherical as well as wobbling bubbles and thus the interplay of the bubble deformability with the power-law behavior of the liquid bulk. The resulting first- and second-order fluid statistics, i.e., the gas fraction, mean velocity and velocity fluctuation profiles across the channel, show clear trends in reply to varying power-law indexes. In addition, it was observed that the bubble oscillations increase with decreasing power-law index. In the channel core, the bubbles significantly increase the dissipation rate, which, in contrast to its behavior at the wall, shows similar orders of magnitude for all power-law indexes.
Original languageEnglish
Article number40
JournalFluids
Volume6
Issue number1
DOIs
Publication statusPublished - 12 Jan 2021

Keywords

  • Bubbly flow
  • Turbulent channel flow
  • Power-law fluids
  • DNS

Fingerprint Dive into the research topics of 'Turbulent Bubble-Laden Channel Flow of Power-Law Fluids: A Direct Numerical Simulation Study'. Together they form a unique fingerprint.

Cite this