A numerical study of the flow of a low‐density‐polyethylene melt in a planar contraction and comparison to experiments
作者:
Kathleen Feigl,
Hans Christian Öttinger,
期刊:
Journal of Rheology
(AIP Available online 1996)
卷期:
Volume 40,
issue 1
页码: 21-35
ISSN:0148-6055
年代: 1996
DOI:10.1122/1.550736
出版商: The Society of Rheology
关键词: Polyethylene, low‐density;Contraction flow;Simulation;Numerical solution;Finite element methods;COMPUTERIZED SIMULATION;FINITE ELEMENT METHOD;FLOW RATE;POLYETHYLENES;RELAXATION TIME;SHEAR PROPERTIES;SOLUTIONS
数据来源: AIP
摘要:
The flow of a low‐density polyethylene (LDPE) melt in a 10:1 slit‐die contraction at 150°C is simulated by using a two‐dimensional finite element program, and comparisons are made with the experiments of Kramer (1993) who used laser Doppler velocimetry to measure the velocity field at several flow rates. The LDPE melt is modeled by a Rivlin‐Sawyers integral constitutive equation with a spectrum of relaxation times where the parameters were determined from shear and elongational data. Evaluation of the general performance of our model and simulation at several flow rates shows that the simulation accurately predicts the vortex size but underpredicts the velocity overshoot along the centerline. Repeating Kramer’s particle tracking analysis of the flow field at one flow rate for a given set of streamlines we find good quantitative agreement for the elongation rates and relative stretch ratio, but we find our simulation generally underpredicts the shear rates and relative shear strain.
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