Volume–Geometry–Shear Rate ( VGS ) Coordinated Similarity Scale‐Up Method for Safe and Equivalent Mixing of Energetic Materials in Twin‐Screw Extrusion

ABSTRACT The scale‐up of twin‐screw extrusion for energetic materials is challenging due to their sensitivity to heat and shear. Conventional methods often fail to simultaneously ensure process safety and mixing uniformity. This study proposes a novel Volume–Geometry–Shear rate (VGS) coordinated similarity scale‐up method to achieve equivalent safety and mixing performance. Based on a validated φ20 mm benchmark extruder (5 kg/h), safety boundaries were defined via coupled 3D Polyflow and 1D Ludovic simulations. The VGS framework integrates volumetric similarity for throughput, geometric similarity for flow structure, and constant average shear rate for material integrity. When used to design a φ50 mm industrial extruder (30 kg/h), the method greatly improved safety by lowering the maximum pressure, shear stress, and viscous dissipation by 18.9%, 58.2%, and 95.93%, respectively. Meanwhile, mixing performance was preserved with a negligible deviation of < 0.6% in the overall mixing coefficient. The VGS methodology provides a robust, generalizable framework for the safe and efficient industrial scale up of energetic material extrusion.