Transport phenomena in an agitated vessel with an eccentrically located impeller
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Magdalena Cudak
,
Joanna Karcz
Abstract
The paper presents results of an experimental analysis of the transport phenomena at the vicinity of the wall of an unbaffled agitated vessel with an eccentrically located impeller. Distributions of the transport coefficients were experimentally studied using an electrochemical method within the turbulent regime of the Newtonian liquid flow. Measurements were carried out in an agitated vessel with the inner diameter T = 0.3 m. Liquid height in the vessel was equal to the inner diameter, H = T. The agitated vessel was equipped with a Rushton or a Smith turbine or an A 315 impeller. Eccentricity of the impeller shaft was varied from 0 to 0.53. Local values of the dimensionless shear rate, shear stress, dynamic velocity and friction coefficient were integrated numerically for the whole surface area of the cylindrical wall of the vessel. Averaged values of these quantities were correlated with the impeller eccentricity and modified Reynolds number. The proposed Eqs. (5)–(8), with the coefficients given in Table 2, have no equivalent in open literature concerning this subject. Distributions of the shear rate, γ/n, and friction coefficient, f, at the vicinity of the cylindrical wall of the unbaffled vessel equipped with eccentric Rushton or Smith turbine or A 315 impeller are very uneven and they depend significantly on the impeller eccentricity, e/R. Maximum local values of these variables are located on the wall section closest to the impeller blades. From among the tested impellers, the greatest effects of the impeller eccentricity, e/R, and the liquid turbulence (described by the modified Reynolds number Re P,M) on the averaged dimensionless shear rate (γ/n)m and friction coefficient, f m, are found for the radial-flow Rushton turbine located eccentrically in an unbaffled agitated vessel.
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© 2010 Institute of Chemistry, Slovak Academy of Sciences
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Artikel in diesem Heft
- Mechanisms controlling lipid accumulation and polyunsaturated fatty acid synthesis in oleaginous fungi
- Predicting retention indices of aliphatic hydrocarbons on stationary phases modified with metallocyclams using quantitative structure-retention relationships
- New SPME fibre for analysis of mequinol emitted from DVDs
- Continuous production of citric acid from raw glycerol by Yarrowia lipolytica in cell recycle cultivation
- Enhancing the production of gamma-linolenic acid in Hansenula polymorpha by fed-batch fermentation using response surface methodology
- Process characteristics for a gas—liquid system agitated in a vessel equipped with a turbine impeller and tubular baffles
- Kinetic study of pyrolysis of waste water treatment plant sludge
- Transport phenomena in an agitated vessel with an eccentrically located impeller
- Membrane extraction of 1-phenylethanol from fermentation solution
- Theoretical study on transesterification in a combined process consisting of a reactive distillation column and a pervaporation unit
- Wall effects on terminal falling velocity of spherical particles moving in a Carreau model fluid
- The effect of the physical properties of the liquid phase on the gas-liquid mass transfer coefficient in two- and three-phase agitated systems
- Effectiveness of nitric oxide ozonation
- Modelling of nanocrystalline iron nitriding process — influence of specific surface area
- Effect of CeO2 and Sb2O3 on the phase transformation and optical properties of photostable titanium dioxide
- Carnauba wax microparticles produced by melt dispersion technique
- Complexation studies of 3-substituted β-diketones with selected d- and f-metal ions
- Influence of the solvent donor number on the O/W partition ratio of Cu(II) complexes of 1,2-dialkylimidazoles
- Continuous dialysis of sulphuric acid in the presence of zinc sulphate
- Differences in affinity of arylstilbazolium derivatives to tetraplex structures
- Fast ferritin immunoassay on PDMS microchips
