Flow foam phenomena in sudden expansions and contractions

Nitin Deshpande, Mostafa Barigou

Research output: Contribution to journalArticle

29 Citations (Scopus)


A sudden change in how area induces complex transient processes in foams, which increase in significance with increasing flowrate. The effects are a function of the method of foam generation and, hence, depend on the initial foam structure. In vertical upflow at a sudden expansion or contraction, a substantial fraction of the liquid in the foam drains back upstream. This leads to a greatly reduced liquid holdup downstream and a recirculating flow regime upstream. For the area ratios of the fittings investigated, the extent of liquid holdup reduction was less pronounced in the case of a sudden contraction. At low gas rates, a plug flow regime usually existed on either side of the fitting; however, with an increase in gas throughput the presence of the fitting led to the establishment of a recirculating flow regime upstream. At sufficiently high flowrates complete breakdown of foam structure occurred resulting in the onset of a 'flooding' regime downstream. Foam rheology was successfully described by a two-parameter power-law model, and the friction factor for foam flow could be described by a simple explicit relationship. (C) 2001 Elsevier Science Ltd. All rights reserved.
Original languageEnglish
Pages (from-to)1463-1477
Number of pages15
JournalInternational Journal of Multiphase Flow
Issue number8
Publication statusPublished - 1 Aug 2001


  • gamma-ray absorption
  • contraction
  • expansion
  • foam flow
  • pressure drop
  • friction factor
  • liquid holdup


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