A consistent dimensional analysis of gas–liquid mass transfer in an aerated stirred tank containing purely viscous fluids with shear-thinning properties

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 184; pp. 42 - 56
• Main Authors: Hassan, Raouf, Loubiere, Karine, Legrand, Jack, Delaplace, Guillaume
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2012; Elsevier
• Subjects: Aerated stirred tank; Chemical engineering; Chemical Sciences; Dimensional analysis; Gas–liquid mass transfer; mass transfer; mixing; Model of Williamson–Cross; Shear-thinning fluids; Variable material property; viscosity; Aerated stirred tank; Shear-thinning fluids; Model of Williamson–Cross; Variable material property; Dimensional analysis; Gas–liquid mass transfer; Model of Williamson-Cross; Gas-liquid mass transfer
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2011.12.066

► We investigated gas–liquid mass transfer in an aerated stirred tank. ► The focus was on purely viscous fluids with shear-thinning properties. ► The theory of similarity was extended to the cases of variable material properties. ► A single π-space was rigorously built for both Newtonian and non-Newtonian fluids. ► All the mass transfer rates were modelled by an unique dimensionless correlation. This paper deals with gas–liquid mass transfer in an aerated stirred tank containing Newtonian or shear-thinning fluids. The aim is to demonstrate that, for a given mixing system, an unique dimensionless correlation gathering all the mass transfer rates (150 kla measurements) can be obtained if and only if the variability of the rheological material parameters is correctly considered when implementing the theory of similarity. More particularly, it is clearly illustrated that a too gross simplification in the relevant list of the parameters characterizing the dependence of apparent viscosity with shear rates leads to pitfalls when building the π-space set. This is then a striking example showing that a robust predictive correlation can be established when the non-constancy of fluid physical properties ceases to be neglected.