基于周期性边界条件的双螺杆挤出仿真降阶模型与验证OA

To address the high computational cost of conventional computational fluid dynamics(CFD)simulations for the twin-screw extrusion process,a reduced-order model based on periodic boundary conditions is proposed.Conventional and periodic models were established.The Bird-Carreau model was employed to describe the rheological characteristics of the polylactic acid(PLA)melt.A systematic comparison was conducted on the shear rate,velocity,residence time distribution,maximum shear stress,and mixing index in the flow fields of co-rotating and counter-rotating twin-screw extruders.The results show that compared to the conventional model,the periodic model reduces the mesh size and computation time per step by approximately 70%,and the total computation time is saved by over 90%.In the fully developed flow region,the periodic model can replicate the flow field structure and mixing characteristics revealed by the conventional model,with an average error of less than 3%for key physical quantities.This study achieves an order-of-magnitude improvement in computational efficiency while maintaining high accuracy.The proposed method is suitable for the rapid performance evaluation and optimization design of screw elements,demonstrating significant engineering application value.