The effect of inlet conditions on concentrated suspension flows in abrupt expansions

Tracey Moraczewski, Nina C. Shapley

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11 Scopus citations


This work explores the influence of inlet conditions on the particle concentration distribution and flow field of a concentrated suspension undergoing steady flow in an abrupt, axisymmetric 1:4 expansion. Specifically, we consider the impact of inlet conditions in the upstream narrow tube on the resulting downstream profiles. Particle concentration and velocity profiles were measured by using nuclear magnetic resonance imaging. Experiments were conducted with two contrasting inlet tube lengths of 10d1 and 128d1, where d1 is the diameter of the narrow inlet tube. In the short inlet case, none of the particle concentration fields were fully developed upon entering the expansion, whereas several of the suspensions had fully developed profiles in the long inlet case. Results indicate that concentration differences between the core and annular regions were greater for the cases with a long inlet tube than in cases with a short inlet tube, likely owing to the higher degree of particle migration occurring in the long inlet tube before entry into the expansion. Also, the lengths of recirculating regions were greater for suspensions in the long inlet than in the short inlet geometry, while both systems followed the same trend of increasing recirculation length with bulk particle volume fraction and correlation with the ratio of tube center to wall concentration values.

Original languageEnglish (US)
Article number123303
JournalPhysics of Fluids
Issue number12
StatePublished - Dec 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


  • Flow visualisation
  • Non-Newtonian flow
  • Non-Newtonian fluids
  • Pipe flow
  • Suspensions
  • Two-phase flow


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