Turbulent pipe flow of thixotropic fluids

• Tipo: Artigo em Revista Científica Internacional
• Data: 2002

Autores

Pereira, AS (Autor) Outra; F. T. Pinho (Autor) FEUP

Revista

Título: International Journal of Heat and Fluid Flow

Vol. 23

Páginas: 36-51

ISSN: 0142-727X

Editora: Elsevier

Indexação

ISI Web of Knowledge - 18 Citações

ISI Web of Science

Scopus - 23 Citações

Outras Informações

ID Authenticus: P-000-QEY

DOI: 10.1016/s0142-727x(01)00131-x

Abstract (EN): In this work, aqueous suspensions of 1% and 1.5% by weight laponite and a blend of 0.5%/0.07% laponite/carboxymethil cellulose (CMC) are investigated in terms of their rheology and hydrodynamic behaviour in pipe flows. All fluids were shear-thinning, thixotropic and had an yield stress which was measured by direct and indirect methods. The oscillatory tests showed that the 1% laponite suspension was inelastic but the other two fluids exhibited some degree of elasticity. The turbulent pipe flow measurements showed a small amount of drag reduction for the pure laponite suspensions, which was basically accounted for by shear-thinning at Reynolds numbers in excess of 35,000, whereas for the polymer-clay blend the drag reduction was significantly more intense. This work confirmed findings in the literature that the equilibrium condition in the pipe flow was different from the equilibrium condition in the flow curve, which caused some difficulties in data interpretation. However, it found negligible drag reduction for the flow of pure 1.5% laponite suspensions at Reynolds numbers in excess of 60,000, in contradiction to previous findings.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 16