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Viscoelastic behavior of molten polymers in porous media
Author(s) -
Siskovic Nandor,
Gregory Dale R.,
Griskey Richard G.
Publication year - 1971
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690170209
Subject(s) - viscoelasticity , deborah number , porous medium , thermodynamics , power law , polymer , mechanics , reynolds number , newtonian fluid , curvature , porosity , work (physics) , viscosity , materials science , flow (mathematics) , shear stress , shear rate , physics , mathematics , composite material , geometry , statistics , turbulence
The modification of the Blake‐Kozeny equation for porous media flow using the power law has been shown to hold for molten polymers as well as for the previous cases for polymer solutions. The present work extended the correlation of friction factor with Reynolds number an additional three decades. It was also shown, however, that the modified Blake‐Kozeny equation broke down when bed shear rates were in the range of excessive curvature on the polymer flow curves (shear stress‐shear rate). In such cases it is suggested that the Newtonian Blake‐Kozeny equation, together with apparent viscosity data, could be used to correlate such porous media flow of non‐Newtonians. Appearance of viscoelastic effects at the critical Deborah number value of 0.05 predicted earlier were not found to hold. The data of the present investigation show that such a critical value must be at least 0.19 or even higher. This result helps to resolve partially the anomalous results obtained by previous investigators.