Simulation of non‐Newtonian flows in a partially filled twin‐screw extruder by smoothed particle hydrodynamics

This study considered numerical applications of smoothed particle hydrodynamics (SPH) to non‐Newtonian flow in filled or partially filled conveying elements of twin‐screw extruders (TSEs). The algorithms were validated by using a plane Poiseuille flow. Two geometrical configurations with different gap were investigated. A large sound speed was used to prevent particles penetrating the wall boundary of the complex geometry. The velocity field and flow rate of Newtonian flow and non‐Newtonian flow (power law) in filled model and partially filled model were analyzed. The distribution of particles in partially filled conveying element in one rotation is introduced. The rheological properties of material take important effect on the flow in fully filled and partially filled cases. For the fully filled cases, the screw–barrel clearance takes important effect on the flow due to the leakage flow reducing the flow rate. For the partially filled case, the clearance affects the non‐Newtonian flow by changing the rheological properties of the fluid. The effect of clearance on Newtonian flow is very limited due to no back pressure in the partially filled case. This work prepared a groundwork for the accurate analysis of real extrusion by SPH. Distributions of particles in the half filled conveying element.