Experimental and numerical investigations of pressure drop in a rectangular duct with modified power law fluids

Simsoo Park, Dong Ryul Lee

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Numerical solutions are presented for fully developed laminar flow for a modified power law fluid (MPL) in a rectangular duct. The solutions are applicable to pseudoplastic fluids over a wide shear rate range from Newtonian behavior at low shear rates, through a transition region, to power law behavior at higher shear rates. The analysis identified a dimensionless shear rate parameter which, for a given set of operating conditions, specifies where in the shear rate range a particular system is operating, i.e. in the Newtonian, transition, or power law regions. The numerical results of the friction factor times Reynolds number for the Newtonian and power law region are compared with previously published results showing agreement within 0.05% in the Newtonian region, and 0.9% and 5.1% in the power law region. Rheological flow curves were measured for three CMC-7H4 solutions and were found to be well represented by the MPL constitutive equation. The friction factor times Reynolds number values were measured in the transition region for which previous measurements were unavailable. Good agreement was found between experiment and calculation thus confirming the validity of the analysis.

Original languageEnglish
Pages (from-to)645-655
Number of pages11
JournalHeat and Mass Transfer/Waerme- und Stoffuebertragung
Issue number8-9
Publication statusPublished - 2003 Sept


  • Friction factor in internal flow
  • Modified power law
  • Non-Newtonian fluid flow
  • Non-circular duct flow
  • Pressure drop in internal flow

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Fluid Flow and Transfer Processes


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