Direct numerical simulation of the drag force in bubble swarms

W. Dijkhuizen, M. van Sint Annaland, J.A.M. Kuipers

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Abstract

This paper studies the swarm effect on the drag force in bubbly flows. From literature it is well-known that for relatively small bubbles, the drag force increases with the bubble hold-up due to additional hindrance experienced by the bubbles caused by the modified flow field. Very large (spherical cap) bubbles on the other hand may rise cooperatively. The unique capabilities of a 3D Front Tracking model were used to investigate the influence of important parameters like the gas fraction, Reynolds number and the bubble size independently. It was found that the relative drag force increases for bubbles in the range of 2 to 5 mm when the gas fraction is increased up to 13%, while the bubbles become more spherical. Also the influence of the Reynolds number and the bubble aspect ratio on the increased drag force has been determined. It can be concluded that there is only a very weak effect over several decades of the Reynolds number, while there is a strong effect of the bubble aspect ratio. This also helps explaining why the increase in drag is smaller for larger bubbles: when the gas fraction is increased deformable bubbles become more spherical, thus reducing the drag force.
Original languageUndefined
Title of host publication6th International Conference on Multiphase Flow, ICMF 2007
Pages-
Number of pages9
Publication statusPublished - 9 Jul 2007
Event6th International Conference on Multiphase Flow, ICMF 2007 - Leipzig, Germany
Duration: 9 Jul 200713 Jul 2007
Conference number: 6

Publication series

Name
Volume227

Conference

Conference6th International Conference on Multiphase Flow, ICMF 2007
Abbreviated titleICMF
CountryGermany
CityLeipzig
Period9/07/0713/07/07

Keywords

  • IR-68813
  • METIS-245462

Cite this

Dijkhuizen, W., van Sint Annaland, M., & Kuipers, J. A. M. (2007). Direct numerical simulation of the drag force in bubble swarms. In 6th International Conference on Multiphase Flow, ICMF 2007 (pp. -)