Collect. Czech. Chem. Commun.
1992, 57, 1053-1064
https://doi.org/10.1135/cccc19921053
Study of Spatial Distribution of Kinetic Energy of Turbulence in a Cylindrical System with Turbine Impellers and Radial Baffles
Ivan Fořta, Petr Ettlerb, František Kolínb, Juris Vanagsc and Maris A. Rikmanisc
a Department of Chemical and Food Process Equipment Design, Czech Technical University, 166 07 Prague 6, Czechoslovakia
b Microbial Institute, Czechoslovak Academy of Sciences, 142 20 Prague 4, Czechoslovakia
c Institute of Wood Chemistry, Latvian Academy of Sciences, 226 006 Riga, Latvia
Abstract
The paper deals with the description and results of experimental investigation of spatial distribution of kinetic energy of turbulence in a cylindrical system with one or two standard turbine impellers on the same shaft and with radial bafflers at the vessel wall. The time-averaged specific kinetic energy of turbulence of agitated liquid is measured with a stirring-intensity-meter (SIM) consisting of mechanical-piezoelectric sensor and an auxiliary electronic device for processing the scanned fluctuation signal (the SIM calibration was carried out by means of a lasser-doppler anemometer). The measurements were performed in a model vessel of diameter D = 350 mm, in the range of values of Reynolds number for mixing ReM ∈ <1.2.103, 1.06.105> and relative size of impeller and vessel d/D = 0.286 in the single-phase and two-phase system (air was blown into the system through a sparger ring under the lower impeller). It follows from the measured and processed results that the spatial distribution of mean specific kinetic energy of turbulence in systems wit turbine impellers is considerably influenced by the amount of blown air: the mean specific kinetic energy of turbulence decreases with growing volumetric flow rate of air in the stream streaking from blades of rotating impeller, and, in the region outside this stream, it significantly increases.
