Mathematical model of HDPE in extrusion through a converging die
The velocity and vorticity functions, shear stress, and normal stress difference values of a viscoelastic polymeric melt in a converging flow were predicted in this study. This analysis was made by using four constitutive equations: Newtonian; Power Law; a Coleman-Noll Second Order model which assumes that all three material parameter are independent of the second invarient of the rate of deformation; and a Coleman-Noll Second Order model with a Power Law viscosity parameter. In this investigation, the velocity in the ?-direction was not assumed to be zero and the initial terms in the momentum balance were retained, and the technique of Inner-Outer Iteration was used. The material investigated was high-density polyethylene. The results indicated that the velocity in the r-direction at the centerline for a Power Law fluid is a function of both r and N (Power Law exponent constant). From the stress contour lines, it was concluded that if a Coleman-Noll Second Order model is used, the viscosity should be non-Newtonian, e.g., Power Law. A comparison was also made of previously determined results with the theoretically predicted ones in this analysis.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:converging die coleman noll second order model polyethylene hdpe
Date of Publication:01/01/1984