Chamfer‐Induced Flow Modulation at the Spindle Inlet for Fiber Waste Reduction in Vortex Spinning

ABSTRACT Owing to the deficiency of the nozzle structure, the high rate of fiber wastes during the vortex spinning process remains a persistent challenge for high‐quality polymeric yarn manufacturing. To this aim, this work incorporates chamfer to the spindle inlet where yarn formation takes place inside the vortex spinning nozzle to modulate the flow behavior. A computational fluid dynamics model, which employs large eddy simulation to address the complex transient characteristics of swirling flow inside the nozzle, is established. A parametric modeling approach using scripting languages is implemented to automate the simulation process. The results show that the airstream is guided to flow along the chamfered surface at the spindle inlet, which effectively weakens the interaction between vortices and increases the swirl intensity so that fiber wrapping quality in the yarn can be improved. A smaller chamfer angle increases both the intensity and stability of the vortices. Furthermore, the pulling effect of the swirling flow on the fibers can be weakened and fiber wastes can be reduced as a result of the increase of both tangential and radial velocity components of the airflow within the spindle inlet region. However, an excessively small chamfer angle aggravates the circumferential distribution unevenness of the swirl intensity and reduces the tangential velocity in the annular zone, potentially leading to irregular and insufficient fiber wrapping. Yarn spinning experiment is employed to verify the simulation results. This work establishes a reliable numerical framework for improving manufacturing efficiencies and qualities of polymeric yarns through precise design of key geometric parameters.