Trajectories of fibers and analysis of yarn quality for compact spinning with pneumatic groove

To study the motion trajectory of a fiber bundle in the flow field of compact spinning system with pneumatic groove, the computational fluid dynamics model was established and resolved by numerical computation using FLUENT software. The dynamics of the infinitesimal element of a fiber in the flow zone was also established. The dynamic model was solved by utilizing the self-designed MATLAB procedure, and the motion trajectory of the fiber in the flow zone was derived. Results of this research confirmed that before the fiber bundle reaches the groove, it is condensed only by the effect of airflow, and when sliding into the groove, it is affected by both airflow and the shape of the groove. Edge fibers of the fiber bundle are condensed by airflow, and the condensing width of fibers is dependent upon the effect of air flow. The position of fibers of different widths change as a result of airflow, and the phenomenon of migration of fibers takes place in the section of the fiber bundle. Compared with the conventional ring-spun yarn, both the tensile strength and the breaking strength of the compact-spun yarn are enhanced, in particular by reducing yarn hairiness.