Abstract
In this study, a collocated cell-centered finite volume method is developed to simulate the multilayer coextrusion process, which co-extrude two or more layers of non-isothermal generalized Newtonian fluid in a feedblock. This research will predict the velocity, pressure, temperature fields and free surface distribution in three-dimensional space. With different computational parameters, we analyze and discuss the simulation results. Comparing simulation results with past analysis data, we proof that the method used in this study can accurately simulate the flow behavior and free surface distribution in the feedblock of two-layer coextrusion process. We discover that the free surface tends to shift towards the layer with less viscosity or less flow rate, and the encapsulation phenomena occurs for the balance of stresses on free surface. Furthermore, the difference of the initial merging height and contact angle also causes different distortion of free surface. According to the simulation results of two-layer coextrusion with modified Cross model, we observe that the free surface shifts towards the more sensitive material layer by increasing flow rate or temperature, and it is due to the effect of viscosity decrease. Later, we apply this method to three-layer and five-layer coextrusion simulation, and it can also predict the flow behavior and free surface distribution in these more complex systems.