Detailed LDV measurements for visualization of the flow field within a stirred-tank reactor equipped with a Rushton turbine

This paper presents the results obtained during investigations carried out on a multifunctional stirrer test rig which was established at the Institute of Fluid Mechanics at the University of Erlangen-Nuremberg. The objective of the research work was to generate a reliable data basis for the validation of numerical simulations of the flow field in stirred-tank reactors. For the measurements advanced laser Doppler velocimetry including full refractive index matching and automated data acquisition was used. The flow field in this case was induced by a Rushton turbine which was constructed of transparent material in order to gain access to the important flow field within the turbine for the first time. The presentation of the large-scale flow field confirms the results presented in previous publications, but a higher resolution was realized. Mean flow and turbulence characteristics are presented. The turbulence length scale L was found to be about half the blade height, which is in good agreement with the length scales reported by other authors for Rushton turbines. The total access to the flow field permitted the mean flow and the turbulence kinetic energy distribution within the stirrer element to be determined in detail.