A fast numerical approach for the simulation of highly viscous non-isothermal non-Newtonian fluids

Abstract

This paper deals with the efficient simulation of polymer melts, as an example of highly viscous non-isothermal non-Newtonian fluids. In flow fields of our interest, which are characterized by small Reynolds numbers and large Prandtl numbers, steep gradients occur in thin boundary layers of the temperature distribution, whereas the boundary layers associated with the velocity field possess a considerable different length scale. In order to benefit from these properties, we introduce a physically motivated multigrid approach by computing velocity and temperature fields on different meshes. This new development is achieved by the modification of a discrete projection method. Numerical experiments are presented which confirm that the method decreases the computational effort considerably, while preserving the numerical accuracy. (2000). Primary 76A05 · Secondary 76D05 · 76M10. Mathematics Subject Classification

Computational Modeling of the Effects of Viscous Dissipation on Polymer Melt Flow Behavior During Injection Molding Process in Plane Channels

“…The recent numerical studies [6][7][8][9][10], on the other hand, present more complete simulation solutions for viscous dissipation effects on thermodynamic transport characteristics of polymer melt flow in mold and cavities. These numerical studies/efforts aim at improving existing numerical modeling capabilities for a full understanding of the polymer process dynamics with viscous heating.…”

“…The heat generated by viscous friction leads to a local temperature increase especially in the high shear layer regions in the vicinity of the wall surfaces which in turn reduces the viscosity of the polymer melt flow in these regions and this may significantly change the local flow and heat transfer characteristics of the polymer melt flow during the manufacturing process. Therefore, studying of viscous dissipation effects on the polymer melt flow in the analytical [2-5] and numerical [6][7][8][9][10] investigations has received a great attention in recent years for the optimization of existing manufacturing processes in addition to alternative research studies [11,12] for analyzing effects of nanoparticles and processing conditions on the development of local microstructures under thermal and deformation fields experienced in injection molding processes. The recent experimental studies [13,14] also emphasize the importance of the viscous dissipation effects in high viscous flows or in presence of high gradients in velocity distributions for polymer process applications of micro channels.…”

Study of Dynamic Flow and Mixing Performances of Tri-Screw Extruders with Finite Element Method

“…Up to now, a number of numerical simulations and experimental researches have been conducted to investigate the flow and mixing mechanism for the extrusion problem of single-screw and twin-screw extruders [3][4][5][6][7]. In addition, the chaotic mixing in the twin-screw or single-screw extruder has been carried out to reveal the stretching and folding actions, using Poincaré section, Lyapunov exponent, and so forth [8][9][10][11].…”