3D-PTV flow measurements of Newtonian and non-Newtonian fluid blending in a batch reactor in the transitional regime

Research output: Contribution to journalArticlepeer-review


Colleges, School and Institutes

External organisations

  • Johnson Matthey Technology Centre


Lagrangian trajectories obtained through 3D Particle Tracking Velocimetry (3D-PTV) measurements have been used to visualize the flow field of Newtonian and non-Newtonian fluids in a flat-bottomed vessel. The vessel, of diameter T=180 mm, was equipped with a 6-blade Rushton turbine of diameter D=T/3 and four baffles of width b=T/10. The experiments were carried out in the transitional flow regime (73≤Re≤1,257). The velocities and Lagrangian accelerations in the flows have been calculated from the time-resolved tracer coordinates. Non-Newtonian fluids exhibited a smaller impeller flow number compared to Newtonian fluids. The distributions of shear rate have been obtained via interpolation of the Lagrangian velocity data in a 3D Eulerian grid. In the impeller region, the mean shear rate was, to a first approximation, proportional to the impeller rotational speed, although a more detailed analysis revealed influences of both rheology and Reynolds number. The mean Lagrangian acceleration scaled with the mean shear rate raised to the power of 1.8.

Bibliographic note

Funding Information: Manuele Romano was supported by the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in Formulation Engineering (EP/L015153/1) and Johnson Matthey Plc. Publisher Copyright: © 2021 Elsevier Ltd


Original languageEnglish
Article number116969
Number of pages14
JournalChemical Engineering Science
Early online date26 Jul 2021
Publication statusE-pub ahead of print - 26 Jul 2021


  • Lagrangian, Mixing, Non-Newtonian, PTV, Stirred tanks, Trajectories, Transitional