Abstract
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.
Original language | English |
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Article number | 116969 |
Number of pages | 14 |
Journal | Chemical Engineering Science |
Volume | 246 |
Early online date | 26 Jul 2021 |
DOIs | |
Publication status | Published - 31 Dec 2021 |
Bibliographical 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
Keywords
- Lagrangian
- Mixing
- Non-Newtonian
- PTV
- Stirred tanks
- Trajectories
- Transitional
ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering