Multiscale simulation of viscoelastic flows : applications to kinetic theory models of polymer melts and liquid crystalline polymers

Knowing and understanding the dynamics and molecular configurations of polymer molecules is important for efficient process design and novel product development. Much research has been focused on combining molecular simulations and traditional fluid mechanics computations to simulate the behavior of polymeric liquids in a fabrication process. These simulation approaches require solution of the coupled set of the equations of change, the governing equations from kinetic theory, and the flux expressions that map molecular configurations to macroscopic quantities. Most complex flow simulations so far make use of a mixed finite element method to calculate the velocity field, with stress tensor evaluated by using a stochastic simulation method. This so-called CONNFFESSIT approach suffers from both a large memory requirement and stochastic noise. This thesis focuses on the development and application of a fully deterministic numerical approach for computing viscoelastic flows with constitutive descriptions based directly on diffusion equations from kinetic theory. The numerical approach is based on an operator splitting time integration method that decouples the calculation of microstructure by solution of a hyperbolic diffusion equation from the velocity and pressure field evolution, which is obtained by solution of a generalized Stokes problem. The generalized Stokes problem is written in the DEVSS-G formulation, where a direct interpolation of the components of the velocity gradient tensor is introduced. The efficiency and robustness of this numerical method is demonstrated through calculating the viscoelastic flows of a modified Doi model for liquid crystalline polymer and a number of reptation models for polymer melts in different flow geometries.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Suen, Jason Ka-Chun, 1973-

Advisor dc:contributor.advisor

• Robert C. Armstrong.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29293

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29293