Evaluation and accuracy of the local velocity data measurements in an agitated vessel

¹ Institute of Hydrodynamics, AS CR, v.v.i. Pod Patankou 30/5, 16612 Prague 6, Czech Republic
² Institute for Nanomaterials, Advanced Technology and Innovation, Technical University of Liberec Studentska 1402/2, Liberec, Czech Republic

^a Corresponding author: kysela@ih.cas.cz

Published online: 25 March 2014

Abstract

Velocity measurements of the flow field in an agitated vessel are necessary for the improvement and better understanding of the mixing processes. The obtained results are used for the calculations of the impeller pumping capacity, comparison of the power consumption etc. We performed various measurements of the local velocities in an agitated vessel final results of which should be processed for several purposes so it was necessary to make an analysis of the obtained data suitability and their quality. Analysed velocity data were obtained from the LDA (Laser Doppler Anemometry) and PIV (Particle Image Velocimetry) measurements performed on a standard equipment where the flat bottomed vessel with four baffles was agitated by the six-blade Rushton turbine. The results from both used methods were compared. The frequency analyses were examined as well as the dependency of the data rates, time series lengths etc. The demands for the data processed in the form of the ensemble-averaged results were also established.