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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF THE THERMAL CONVECTION FOR HERSCHEL-BULKLEY FLUID IN THE ENTRANCE REGION OF A DUCT

Get access (open in a dialog) DOI: 10.1615/IHTC10.2930
pages 297-302

Résumé

The thermal convection, with constant heat flux for non-Newtonian fluids in the entrance region of a duct is studied theoretically and experimentally. In the theoretical analysis it is assumed that: (i) the rheological behavior of the fluid can be expressed through the Herschel-Bulkley law: τ = τs + K γn; (ii) the now is fully developed at the entry; (iii) all fluid properties, other than consistency index are constant. The K-T relation used is K = K0exp (−b T). Indeed in this analysis, viscous dissipation is taken into account. Velocity measurements for isothermal and heating situation, reveal the incidence of the imposed thermal field on the flow structure. It is characterized by an increase of shear rate at the wall, and of the size of the yield dimension. Temperature measurements permit the study of the local heat transfer. Finally, a correlation is proposed taking into account the modification of the wall shear rate induced by the rheological properties and the temperature dependent character of the fluid.