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.
Romano M.G., Alberini F., Liu L., Simmons M.J.H., Stitt E.H. (2021). 3D-PTV flow measurements of Newtonian and non-Newtonian fluid blending in a batch reactor in the transitional regime. CHEMICAL ENGINEERING SCIENCE, 246, 116969-116977 [10.1016/j.ces.2021.116969].
3D-PTV flow measurements of Newtonian and non-Newtonian fluid blending in a batch reactor in the transitional regime
Alberini F.
;
2021
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
