Polymer drag reduction in surfactant-contaminated turbulent bubbly channel flows

Daulet Izbassarov, Zaheer Ahmed, Pedro Costa, Ville Vuorinen, Outi Tammisola, Metin Muradoglu*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Polymer additives are commonly utilized to manipulate bubbly flows in various applications. Here we investigate the effects of clean and contaminated bubbles driven upward (upflow) in Newtonian and viscoelastic turbulent channel flows. Interface-resolved direct numerical simulations are performed to examine sole and combined effects of soluble surfactant and viscoelasticity using an efficient three-dimensional finite-difference-front-tracking method. The incompressible flow equations are solved fully coupled with the FENE-P viscoelastic model and the equations governing interfacial and bulk surfactant concentrations. The latter coupling is accomplished by a nonlinear equation of state that relates the surface tension to the surfactant concentration. For Newtonian turbulent bubbly flows, the effects of Triton X-100 and 1-pentanol surfactant are examined. It is observed that the sorption kinetics highly affect the dynamics of bubbly flow. A minute amount of Triton X-100 is found to be sufficient to prevent the formation of bubble clusters restoring the single-phase behavior while even two orders of magnitude more 1-pentanol surfactant is not adequate to prevent the formation of layers. For viscoelastic turbulent flows, it is found that the viscoelasticity promotes formation of the bubble wall-layers and thus the polymer drag reduction is completely lost for the surfactant-free bubbly flows, while the addition of small amount of surfactant (Triton X-100) in this system restores the polymer drag reduction resulting in 25% drag reduction for the Wi = 4 case.

Original languageEnglish
Article number104302
Number of pages22
JournalPhysical Review Fluids
Volume6
Issue number10
DOIs
Publication statusPublished - 4 Oct 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • DIRECT NUMERICAL SIMULATIONS
  • FRONT-TRACKING METHOD
  • SPHERICAL BUBBLES
  • IDENTIFICATION
  • MIGRATION
  • SCHEME
  • SIZE

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