scholarly journals Effects of baffle on flow structure and cyclic variation in stirred tanks with Rushton turbine

AIP Advances ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 015202
Author(s):  
Ying Fan ◽  
Jiao Sun ◽  
Jie Jin ◽  
Kangfu Sun ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Flow Structure ◽  
Cyclic Variation ◽  
Stirred Tanks ◽  
Rushton Turbine

PIV study of small-scale flow structure around a Rushton turbine

AIChE Journal ◽  
2001 ◽  
Vol 47 (4) ◽  
pp. 766-778 ◽  
Author(s):  
K. V. Sharp ◽  
R. J. Adrian
Keyword(s):  
Flow Structure ◽  
Small Scale ◽  
Rushton Turbine

scholarly journals CFD study of the effect of Baffles on the energy consumption and the flow structure in a vessel stirred by a Rushton turbine

Mechanika ◽  
2016 ◽  
Vol 22 (3) ◽  
Author(s):  
Kamla Youcef ◽  
M. Bouzit ◽  
A. Hadjeb ◽  
I.M. Arab ◽  
M. Beloudane
Keyword(s):  
Energy Consumption ◽  
Flow Structure ◽  
Rushton Turbine

scholarly journals Effects of Impeller Geometry on the 11α-Hydroxylation of Canrenone in Rushton Turbine Stirred Tanks

2021 ◽  
Author(s):  
Shaofeng Rong ◽  
Xiaoqing Tang ◽  
Shimin Guan ◽  
Botao Zhang ◽  
Qianqian Li ◽  
...  
Keyword(s):  
Stirred Tanks ◽  
Rushton Turbine ◽  
Impeller Geometry

scholarly journals Modeling of bubble break-up in stirred tanks

2004 ◽  
Vol 8 (1) ◽  
pp. 29-50 ◽  
Author(s):  
Goran Zivkovic ◽  
Stevan Nemoda
Keyword(s):  
Bubble Diameter ◽  
Turbulent Regime ◽  
Flow Modeling ◽  
Stirred Tanks ◽  
Rushton Turbine ◽  
Phase Doppler Anemometry ◽  
Different Types ◽  
Break Up ◽  
Almost All ◽  
Good Agreement

The Lagrangian code LAG3D for dispersed phase flow modeling was implemented with the introduction of bubble break-up model. The research was restricted on bubbles with diameter less than 2 mm, i.e. bubbles which could be treated as spheres. The model was developed according to the approach of Martinez-Bazan model. It was rearranged and adjusted for the use in the particular problem of flow in stirred tanks. Developed model is stochastic one, based on the assumption that shear in the flow induces the break of the bubble. As a dominant parameter a dissipation of the turbulent kinetic energy was used. Computations were performed for two different types of the stirrer: Rushton turbine, and Pitch blade turbine. The geometry of the tank was kept constant (four blades). Two different types of liquids with very big difference in viscosity were used, i.e. silicon oil and dimethylsulfoxide, in order to enable computation of the flow in turbulent regime as well. As a parameter of the flow, the number of rotations of the stirrer was varying. As a result of the computation the fields of velocity of both phases were got, as well as the fields of bubble concentration bubble mean diameter and bubble Sauter diameter. To estimate the influence of the break-up model on the processes in the stirred tank a computations with and without this model were performed and compared. A considerable differences were found not only in the field of bubble diameter, but also in the field of bubble concentration. That confirmed a necessity of the introduction of such model. A comparison with the experiments performed with phase Doppler anemometry technique showed very good agreement in velocity and concentration profiles of the gas phase. The results for the average bubble diameter are qualitatively the same, but in almost all computations about 20% smaller bubble diameter was got than in the measurements.

Macro-instability: a chaotic flow component in stirred tanks

2007 ◽  
Vol 366 (1864) ◽  
pp. 409-418 ◽  
Author(s):  
Pavel Hasal ◽  
Milan Jahoda ◽  
Ivan Fořt
Keyword(s):  
Lyapunov Exponent ◽  
Correlation Dimension ◽  
Fluid Velocity ◽  
Tangential Force ◽  
Axial Component ◽  
Maximum Lyapunov Exponent ◽  
Stirred Tanks ◽  
Operational Conditions ◽  
Rushton Turbine ◽  
Proper Orthogonal

Chaotic features of the macro-instability (MI) of flow patterns in stirred tanks are studied in this paper. Datasets obtained by measuring the axial component of the fluid velocity and the tangential force affecting the baffles are used. Two geometrically identical, flat-bottomed cylindrical mixing tanks (diameter of 0.3 m) stirred with either pitched blade turbine impellers or Rushton turbine impeller are used in the experiments, and water and aqueous glycerol solutions are used as the working liquids. First, the presence of the MI component in the data is examined by spectral analysis. Then, the MI components are identified in the data using the proper orthogonal decomposition (POD) technique. The attractors of the macro-instability are reconstructed using either the POD eigenmodes or a method of delays and finally the attractor invariants are evaluated. The dependence of the correlation dimension and maximum Lyapunov exponent on the vessel operational conditions is determined together with their distribution within the tank. No significant spatial variability of the correlation dimension value is observed. Its value is strongly influenced by impeller speed and by the vessel–impeller geometry. More profound spatial distribution is displayed by the maximum Lyapunov exponent taking distinctly positive values. These two invariants, therefore, can be used to locate distinctive regions with qualitatively different MI dynamics within the stirred tank.

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