Abstract Summary (Max 250 words)
The current design and optimization of mixing processes for non-Newtonian fluids in large industrial-scale vessels rely mainly on CFD simulations or down-scaled experiments. Available experimental techniques are mostly limited to point measurements at fixed positions inside the reactor. Contrary, advanced techniques that provide distributed data, such as PIV/PTV, are hardly adjustable in industrial reactors. Recently, Lagrangian Sensor Particles (LSP) were proposed and tested in industrial scale reactors. These particles follow the flow and log data for pressure, acceleration and spin rate. In this work, the mixing of shear-thinning CMC-solution of different concentrations in a 150 L stirred tank reactor, equipped with a 3-blade PBT running between 150 and 300 rpm is studied numerically and experimentally. Eulerian based CFD simulations are validated with LSP measurements. The LSP data are evaluated by averaging the counts of axial upwards/downwards velocity components, resulting in a mean averaged axial velocity profile along reactor axis. In comparison, in the Euler based simulation the axial velocity components are evaluated by a weighting function. The results indicate a root mean squared error (RSME) between 0.02 m/s and 0.05 m/s with an average velocity between 0.13 m/s and 0.25 m/s. Additionally, the evaluated mean circulation times from simulations are in good accordance with experimental data. Increasing deviations between simulations and measurements at higher CMC concentration (i.e. higher viscosity), reveal a shift to laminar-dominated flow, which cannot be captured by the current model assumptions of the CFD setup.
