Viscoelastic flow in a 3D square/square contraction: Visualizations and simulations

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Alves, MA (Author) FEUP; Pinho, FT (Author) FEUP; Oliveira, PJ (Author) Other

Journal

Title: Journal of Rheology

Vol. 52 No. 6

Pages: 1347-1368

ISSN: 0148-6055

Publisher: Society of Rheology

Indexing

ISI Web of Knowledge - 19 Citations

ISI Web of Science

Scopus - 20 Citations

INSPEC

COMPENDEX

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-003-V85

DOI: 10.1122/1.2982514

Abstract (EN): The inertialess three-dimensional (3D) flow of viscoelastic shear-thinning fluids in a 4:1 sudden square-square contraction was investigated experimentally and numerically and compared with the flow of inelastic fluids. Whereas for a Newtonian fluid the vortex length remains unchanged at low Reynolds numbers, with the non-Newtonian fluid there is a large increase in vortex length with fluid elasticity leading to unstable periodic flow at higher flow rates. In the steady flow regime the vortices are 3D and fluid particles enter the vortex at the middle plane, rotate towards its eye, drift sideways to the corner-plane vortex, rotate to its periphery, and exit to the downstream duct. Such dynamic process is reverse of that observed and predicted with Newtonian fluids. Numerical predictions using a multimode Phan-Thien-Tanner viscoelastic model are found to match the visualizations accurately and in particular are able to replicate the observed flow reversal. The effect of fluid rheology on flow reversal, vortex enhancement, and entry pressure drop is investigated in detail.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 22