Abstract
A numerical method is proposed to calculate local extensional rate along arbitrary streamlines measured experimentally. It leads to the calculation of a “local Deborah number” (De) field, which characterizes heterogeneous flows of polymer solutions in a more insightful way than the commonly used nominal Weissenberg number (Wi), defined by an average shear rate. The spatial distribution of non-equilibrium polymer conformation across flow domain could be visualized through an image of the De field for flows of aqueous semi-dilute polyacrylamide (PAAm) solutions through the 4:1:4, 8:1:8 and 16:1:16 planar contraction geometries, over a range of Wi(1.4⩽Wi⩽131.7) and Elasticity numbers (El) (13.3⩽El⩽476.8). The time evolution of these De fields and their profiles near the contraction plane are presented. The correlation between the maximum local De and the nominal Wi is analyzed. The results show that the vortex formation near the contraction entry coincides with shifting the position of the maximum local De away from the centerline. Its actual location is sensitive to flow rate and strongly depends on dynamic flow regime.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
