An Automated Computational Fluid Dynamics Framework for 3D Multilayer Coextrusion Simulations in Complex Die Geometries

Author(s):

Dayne A. Plemmons

Abstract:

Multilayer coextrusion is a scalable manufacturing technology for producing advanced polymer composites with targeted, micro-, and nanostructured layer architectures. However, achieving precise layer fidelity requires careful optimization of processing conditions and die geometries. Due to the cost and complexity of physical prototyping, predictive computational tools are essential for evaluating layer morphologies and flow stability. We present an automated, open-source computational fluid dynamics (CFD) framework built on the OpenFOAM platform to simulate 3D, two-phase coextrusion flows. The closed-loop workflow integrates parametric CAD generation, automated meshing, generalized Newtonian transport modeling, and quantitative field analysis. Applied to layer-multiplying element (LME) dies used during multilayer coextrusion, the framework effectively captures critical flow phenomena—including viscous encapsulation, shear-thinning-induced layer distortion, and interfacial stress spikes—for both viscosity-matched and mismatched resins. Furthermore, the tool is applied to evaluate and optimize novel LME geometries, demonstrating that maintaining a constant cross sectional area and gradual convergence angles significantly reduces interfacial shear stresses and suppresses layer asymmetry. Ultimately, this predictive framework provides an efficient, scalable tool for guiding LME die design, mitigating processing defects, and targeting exact layer morphologies in advanced polymeric composite manufacturing.