Simulating the motion of a flexible fiber in 3D tangentially injected swirling airflow in a straight pipe-Effects of some parameters

A numerical model for particle-level simulation of fiber suspensions has been used to simulate fiber dynamics in three-dimensional tangentially injected swirling airflow in air-jet spinning nozzles. The fiber is modeled as chains of beads connected through massless rods, and its flexibility is defined by the bending and twisting displacements. The effects of some parameters, such as fiber initial position, the injection angle and the injector diameter on fiber motion and yarn properties are discussed. The springy, snake-like and week helical regimes of fiber motion are observed under the most cases. The far from the tube center the fiber release position, the smaller the fiber flexibility is. For a smaller injection angle, the self-entanglement regimes of fiber motion are observed in the downstream of the injectors. The model also predicted the complex helical configuration in the nozzle with a small injector diameter. The predictions of yarn properties coincide with the experimental results reported by several researchers.