Investigation of the flow patterns and power requirements in agitated systems: effects of the design of baffles and vessel base
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Mohammed Foukrach
Abstract
The flow patterns and power consumption of a six-blade Rushton turbine (RT) in a cylindrical vessel are characterized in this paper. We focus on the effects of the shape of the vessel base by studying two cases: a conical and a dished shape. In addition, the effects of the height of the vessel base (h2) are explored and four cases are considered, namely: h2/D = 1/10, 1/6, 1/5 and 1/3 (D: vessel diameter). In the second part of our investigation, a new design of baffles (a triangular-shaped baffle) is suggested and a comparison is made between the performance of the standard and the triangular baffles. The main findings revealed that the conical shape of the vessel base provides a slight enhancement in the axial circulation at almost the same power input for the dished bottomed vessel. For Re < 2 × 104, the power required by both types of baffles is the same; however, above this value of Re, a reduction by about 4% in power consumption is given by the standard baffles. Also, and for all shapes of baffles and vessel bases, a reduction in power consumption may be obtained by increasing the height of the vessel base.
Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
Symbols
- B
Baffle width, m
- c
Distance between agitator and bottom of the vessel, m
- d
Impeller diameter, m
- D
Vessel diameter, m
- g
gravitational constant, m/s2
- H
Liquid height, m
- h1, L
Baffle length, m
- h2
Height of the vessel base, m
- N
Agitator speed, s−1
- Np
Power number, dimensionless
- P
Power consumption, W
- Qv
Viscous dissipation function, 1/s
- R
Radial coordinate, m
- R*
Dimensionless radial coordinate
- Re
Reynolds number, dimensionless
- V
Velocity, m/s
- Vz
Axial velocity, m/s
- Vθ
Tangential velocity, m/s
- Vr
Radial velocity, m/s
- Z
Axial coordinate, m
- Z*
Dimensionless axial coordinate
- τ
Shear stress, Pa
- ρ
Fluid density, kg/m3
- η
Viscosity, Pa*s
- θ
Angular coordinate, degree
- ω
Angular velocity, rad/s
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Articles in the same Issue
- Review
- Separation and purification of fatty acids by membrane technology: a critical review
- Articles
- Investigation of the flow patterns and power requirements in agitated systems: effects of the design of baffles and vessel base
- Computational fluid dynamics simulation of solid-liquid suspension characteristics in a stirred tank with punched circle package impellers
- Fischer-Tropsch reaction mixture permeation through a silicalite-1 membrane reactor and its effect on the produced hydrocarbons distribution
- Influence of the amine alkyl-chain upon carbon dioxide absorption in G-L-L reactor
- Catalytic performance of cerium-modified ZSM-5 zeolite as a catalyst for the esterification of glycerol with acetic acid
- Numerical study on the effect of planar normal and Halbach magnet arrays on micromixing
- The optimization and statistical analysis of fermentative hydrogen production using Taguchi method
- Mechanism of recovery processes for rare earth and iron from Bayan Obo tailings
- Short Communication
- Design optimization of micromixer with circular mixing chambers (M-CMC) using Taguchi-based grey relational analysis
