Twin‐Screw Extrusion Simulation Using Incompressible Smoothed Particle Hydrodynamics With Body‐Fitted Particle Arrangement and Implicit Viscous Diffusion

This study employs an incompressible smoothed particle hydrodynamics (ISPH) method with implicit treatment of viscous diffusion to simulate polymer flow during twin‐screw extrusion. The ISPH method is combined with a body‐fitted particle arrangement (BFPA) technique, in which an iterative procedure is used to gradually adjust the positions of wall boundary particles in accordance with the prescribed geometry. The ISPH–BFPA approach is first verified for fully filled, isothermal single‐screw extrusion of a non‐Newtonian fluid, showing reasonable agreement with finite volume method results in terms of the cross‐sectionally averaged shear rate. The ISPH–BFPA approach is then applied to partially filled twin‐screw extrusion under nonisothermal, non‐Newtonian conditions, and no obvious numerical instability attributable to the BFPA‐based wall‐particle arrangement is observed. The simulated filling states for two screw configurations are consistent with the polymer distribution observed in dead‐stop experiments. These results demonstrate the applicability of the ISPH–BFPA approach to qualitative and relative analyses of twin‐screw extrusion.