Simulation of polymer molding filling process with an adaptive weld line capturing algorithm

Abstract

A simulation of mold filling with multi-inlets or an insert in the cavity is pursued with an improved Level Set Method. The governing equations for the melt and the air in the cavity are united into one system of Navier-Stokes equations and solved by the finite volume method on the collocated grid. The level set and the reinitialization equation, which is revised according to Sussman et al. to keep mass conservation, are solved by the finite difference method, in which the spatial derivatives are discretized by the 5th-order Weighted Essentially Non-Oscillatory (WENO) scheme, and the temporal derivatives are discretized by the 3rd-order Total Variation Diminishing Runge-Kutta (TVD-R-K) scheme. The validity of the advection scheme is verified by some benchmark problems. An effective algorithm for capturing the position of the weld line is proposed. The cases with different positions and quantities of inlets and different shapes of the insert in different positions are discussed. The positions of the interface at different time, the length and position of the weld line and the press distribution are given and corresponding analysis are made. Numerical results show that the dynamic description of fusion process can be implemented vividly when the cavity has multi-inlets or an insert inside, and the position of the melt at each time step can be determined precisely. Different position and size of the insert lead to different position and length of the weld line. A smaller size insert corresponds to a relatively shorter weld line, while as the width of the insert increases, the length of the weld line increases correspondingly.