A new hyperbolic model and an experimental study for the flow of polymer melts in Multi-Pass Rheometer

摘要

A new mathematical model, and an experimental study are presented for polymeric liquids. The main advantage of the proposed model over the existing models is its hyperbolic nature, which overcomes some of the drawbacks of the available models. One of the advantages of the proposed model is that the boundary conditions can be determined without ambiguity for all variables including the stresses, which may not be the situation for other mixed type systems. The modified Tait equation is used to describe the polymer compressibility and to keep a real set of characteristics for the resulting system of equations. The Giesekus model is used to model the polymer viscoelasticity. A hybrid finite element/finite difference scheme coupled with Newton-Raphson's linearization scheme is used to solve the governing system of equations. Numerical and experimental studies for the flow of polymer melts in a Multi-Pass Rheometer (MPR) are presented. Despite using a one-mode Giesekus model, the predicted shear-rate dependent viscosity curve is in good agreement with the experimental results.