This paper deals with the measurement and modelling of axial liquid dispersion in a 4.5mm internal diameter tube provided with smooth-periodic constrictions (meso-tube) in steady and oscillatory flow conditions. The residence time distribution (RTD) in the meso-tube was monitored for a range of fluid oscillation frequency (f) and amplitude (x0) at laminar flow. The RTD response was modelled with three hydrodynamic models: (i) tanks-in-series, (ii) tanks-in-series with backflow and (iii) plug flow with axial dispersion. The steady flow through the meso-tube at flow rates up to 21.30ml/min resulted in broad RTDs, mainly due to the parabolic velocity profile. The use of fluid oscillations allowed a fine-control of the axial liquid dispersion in the meso-tube due to generation of secondary flow in the regions between the constrictions. The axial dispersion coefficient D was reduced by up to 13-fold in comparison with the steady flow situation. Values of x0≤1mm and f=10Hz generally resulted in a maximum reduction in axial dispersion through, therefore maximum improvements in RTD. The tanks-in-series model was generally not capable of predicting RTDs in the meso-tube. The potential of this platform for the continuous, sustainable production of added-value products is herein demonstrated.

Original languageEnglish
Pages (from-to)793-803
Number of pages11
JournalChemical Engineering and Processing: Process Intensification
Issue number7
Publication statusPublished - 1 Jul 2010


  • Backmixing
  • Continuous
  • Liquid flow
  • Meso-tube
  • Oscillatory flow
  • Smooth-periodic constrictions

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Energy Engineering and Power Technology
  • Process Chemistry and Technology
  • Industrial and Manufacturing Engineering


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