Fiber motion in rotor spinning unit airflow: Numerical simulation and experimental validation.

This article focuses on developing and validating a comprehensive three-dimensional numerical model to simulate the motion of flexible fibers within the airflow of a rotor spinning unit (RSU), a key component in airflow-assisted textile manufacturing. The model represents fibers as chains of cylindrical segments connected by rigid joints, incorporating bending and torsional deformations, and accounts for fluid forces, torques, and fiber–wall interactions, particularly emphasizing the fiber stripping process from the opening roller. Validation through high-speed visualization experiments demonstrates good agreement between simulated and observed fiber trajectories and velocities. Simulations reveal that fibers released from similar initial positions exhibit consistent motion, while those encountering complex airflow patterns, especially near vortices at the transfer channel entrance, experience significant buckling and deformation. A spinning test comparing yarns produced under different fiber entry conditions corroborates the simulation findings, showing that fibers entering from channel sides with more buckling yield yarns with inferior structural and mechanical properties. The study's numerical methodology offers valuable insights for optimizing RSU design and process parameters to improve fiber transport and yarn quality in airflow-assisted spinning.