Abstract:

In order to study the influence of yarn faults on airflow drags yarn, a assumption simulate short slub yarn faults by spheres and cylinders was proposed firstly according to the shape feature of yarn faults in airflow. The drag force of short slub yarn faults were numerical calculated based on analyze airflow results by Fluent. The drag forces of spheres as model of short slub yarn faults were tested by self-designed testing drag force device for main-nozzle air-jet weft insertion under 0.3 MPa inlet pressure. The rationality of numerical calculation that previous statement was verified , and the consistency was obtained. Finally, the influence effect of short slub yarn faults on drag coefficient was studied. Conclusions were found that the rate of change for coefficient of drag force increased firstly then verged to stabilization gradually with the diameter of yarn faults increasing. In addition, the change rate for coefficient of drag force presented descending tendency gradually with increase of the quantity of yarn faults.

Key words: yarn, yarn fault, air drag, numerical calculation, coefficient of drag force