The effect of groove structure on performance of pneumatic spliced joint.

The geometrical structure of splicing chamber has a significant influence on performance of spliced joint with respect to appearance and strength. The air characteristic inside splicing chambers with different structures, namely no groove, 1-mm-width groove, and 2-mm-width groove, were numerically investigated using CFD modeling technology. A spiral ratio of airflow, which is composed by velocity circulation indicating the circumference airflow and average velocity in axial direction, was extracted from the numerical results to describe the role of air flow on the joint forming. The splicing experiments were conducted on the corresponding chambers. The appearance of splicing joint was captured by an optical camera and the splicing strength was evaluated by a yarn strength test machine. The correlation between a spiral ratio of the velocity circulation to the axial average velocity and the performance of spliced joint was verified by analyzing the numerical results and experimental data. With the increase of groove width, the decrease of airflow in axial direction is more obvious than the circumference airflow, leading to larger spiral ratio. As a result, more filaments wrap around the opposite yarn stem and the diameter and strength of spliced joint increase. [ABSTRACT FROM AUTHOR]