Since the particles used in our DEM model are already coarse-grained granular particles, further coarsening them to fit the centimeter-scale extruder size would make the material properties of the particles more ambiguous. Therefore, we choose to linearly reduce the extruder size to a range corresponding to the particle size, in order to reduce computational cost. Meanwhile, because we are not required to consider the maximum torque limitation of the twin-screw in the simulation, we can also simplify the shape of the recirculation circuit to a constant diameter of 60 µm. In the model, we reduce the outlet diameter of the extruder to 60 µm, which is 3000 µm in the experimental device. We reduce the size of the other parts proportionally, thus obtaining a geometric model of the extruder with a volume of around 1.17 × 10 -4 cm 3 .