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Rheology, friction, and heat transfer study of a discontinuously shear-thickening antimisting polymer solution

1987; Elsevier BV; Volume: 25; Issue: 2 Linguagem: Inglês

10.1016/0377-0257(87)85042-5

1873-2631

E.F. Matthys, R. H. Sabersky,

Injection Molding Process and Properties

Abstract Measurements of the viscosity of an antimisting polymer solution in capillaries indicated that this fluid exhibits a complex non-Newtonian nature involving both shear-thinning at low shear rate and abrupt time-dependent shear-thickening past a critical shear rate. Various parameters such as concentration, aging, photodegradation, intentional mechanical degradation, and temperature were shown to have unexpectedly similar effects on the viscous characteristics of the fluid. Extensive friction and heat transfer measurements were also carried out, and it was found that meaningful correlations for these results can be developed if an adequate apparent viscosity model is used for the computations. In particular, all fluid properties must be evaluated at the inner wall temperature, and both the gelation and degradation induced in the test tube itself must be taken into account. It was then possible to show that this peculiar fluid is in fact an asymptotic drag and heat transfer reducer, even though it exhibits dramatic discontinuous shear-thickening characteristics. Various turbulent flow results are presented that were obtained under fully-developed conditions as well as in the very long entrance region observed. It was additionally verified that after severe degradation this fluid can revert to a Newtonian nature as evidenced by its viscosity, friction, and heat transfer properties.