Masters Theses
Date of Award
8-1990
Degree Type
Thesis
Degree Name
Master of Science
Major
Chemical Engineering
Major Professor
Marion G. Hansen
Committee Members
Donald C. Bogue, Frederick E. Weber, Raymond D. Krieg
Abstract
Extruded pipe is made by forcing a molten polymer through an annular die and cooling it; the final properties of the pipe depend on a number of variables, including in particular the cooling step, during which crystallization takes places. An accurate prediction of temperature profile and crystallinity distribution within a semi-crystalline polymer (polypropylene) is of importance in determining the processing conditions. In this study the solidification of the melt during cooling in pipe extrusion has been analyzed by means of a computer simulation. The mathematical model, which involves a steady-state nonlinear energy equation incorporating the crystallization kinetics proposed by Nakamura, simulates the behavior of polymer melt in the cooling chamber during formation of a thick walled pipe. An investigation was carried out into effects of melt inlet temperature, take-off speed, and pipe wall thickness on the temperature profile as well as crystallinity distribution. NACHOS II, a computer program based on finite element method designed for solution of two-dimensional fluid dynamics and heat transfer, is employed for the numerical solution. The numerical model gives therefore a basis for the prediction of the crystallinity distribution and adjustment of the operation conditions.
Recommended Citation
Wu, Jung-He, "Computer simulation of steady-state pipe extrusion. " Master's Thesis, University of Tennessee, 1990.
https://trace.tennessee.edu/utk_gradthes/12807