Some characteristics of stirred vessel flows of dilute polymer solutions powered by an hyperboloid impeller

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Adélio Cavadas (Author) FEUP; Fernando Tavares de Pinho (Author) FEUP

Journal

Title: Canadian Journal of Chemical Engineering

Vol. 82 No. 2

Pages: 289-302

ISSN: 0008-4034

Publisher: Wiley-Blackwell

Indexing

ISI Web of Science

Scientific classification

CORDIS: Technological sciences

Other information

DOI: 10.1002/cjce.5450820210

Abstract (EN): Measurements of the power consumption and mean and turbulent velocities in the wall jet of a stirred vessel flow, powered by a hyperboloid impeller, were carried out. The fluids were aqueous solutions of tylose, CMC and xanthan gum (XG), at weight concentrations ranging from 0.1% to 0.6%, which exhibited varying degrees of shear-thinning and viscoelasticity. The hyperboloid impeller parameter k of Metzner and Otto (1957) was found to be equal to 27.2 ±4. In the Reynolds number range of 103 to 3 × 104 the mixing power was reduced for all non-Newtonian fluids, but never by more than 13%. The flows of the 0.2% CMC and 0.2% XG solutions were found to be less turbulent than those of water, especially for the latter fluid where a reduction in axial rms in excess of 50% was found in the wall jet. This was attributed to elasticity effects and especially to the high zero shear viscosity of the latter fluid.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14