Abstract
The viscoelastic flow of low-density polyethylene melts in a cross-slot channel is studied numerically for the double convected Pom–Pom (DCPP) and single modified DCPP (S–MDCPP) models. The equal low-order finite elements for velocity–pressure–stress variables are implemented to solve the flow fields using the pressure-stabilized iterative fractional step algorithm. The distributions of axial velocity along the channel centerline and the principal stress difference achieved by numerical predictions are in quantitative good agreement with the reported experimental results. Furthermore, the evolution of backbone stretch of macromolecule with flow time is demonstrated, and then an exponential decay function is proposed linking the microscale stretch relaxation time with the macroscale flow time, in order to reveal the stretch relaxation response of the branched polymer. The effects of the Weissenberg number and several constitutive parameters of the S–MDCPP model on the rheological behavior of polymer melts are discussed.
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Acknowledgements
The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China through Contract/Grant numbers 21274072, 11302043, and the State Key Laboratory of Structural Analysis for Industrial Equipment (No. GZ1213) and the Key Laboratory of Rubber–plastics, Ministry of Education (No. KF2010007).
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Wang, W., Hu, C. & Li, W. Time-dependent rheological behavior of branched polymer melts in extensional flows. Mech Time-Depend Mater 20, 123–137 (2016). https://doi.org/10.1007/s11043-015-9287-3
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DOI: https://doi.org/10.1007/s11043-015-9287-3