A Comprehensive Analysis of Weft Yarn Insertion in Air-Jet Weaving Looms Considering Yarn Surface Hairiness

This study investigates the dynamics of weft yarn insertion in air-jet weaving looms, focusing on the influence of yarn surface hairiness. Traditional models treat yarns as smooth cylinders, but real yarns exhibit protruding fibers quantified by the S3 value (fibers longer than 3 mm per 100 meters). A mathematical model was developed to incorporate hairiness by adjusting the drag coefficient and effective diameter. Numerical analysis shows that increased hairiness raises drag force and reduces net force, slightly lowering acceleration, though propulsion force generally sustains insertion speed. The findings emphasize the importance of accurate aerodynamic modeling, as yarn hairiness introduces drag variations that affect weaving efficiency. Future work should refine empirical constants and account for turbulent airflow conditions to optimize loom performance.