Numerical Simulation of Molding Hele-Shaw Flow of Polymeric Liquid Crystals

Abstract

To develop a simulation software which is able to predict the molding flow of polymeric liquid crystals, we present a basic model and its computational procedure. The flow is modeled by the Transversely Isotropic Fluid theory, which is equivalent to the Leslie-Ericksen equations in the high viscosity limit. In the modeling, the Hele-Shaw approximation is applied in order to reduce computational power. Finite difference technique is used to solve governing equations except for the angular momentum equation, which is solved by the streamline integration method. Two thin molds with simple shape are selected to evaluate the model. The computational results for locations of flow front, temperature and molecular orientation profiles show that the model can predict smooth molding process and that molecular orientation depends largely on the position in the gap direction. Since alignment of molecules is disordered by the occurrence of tumbling, which depends on fluid temperature and shear strain, mold temperature and gate position are important for effective molding.