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A core-spun yarn containing an ultrafine copper wire for wearable electronics-oriented applications has been manufactured using a modified vortex spinning system for the first time. The copper wire is fed into the spinning nozzle through a groove on the surface of the top front roller and an orifice through the fiber guiding member in sequence. Scanning electron micrographs confirm that the copper wire locates in the core region and is tightly wrapped by the helical staple fibers of the outer layer in the core-spun yarn, owing to the special yarn formation mechanism of the vortex spinning system. The vortex core-spun yarn containing a copper wire has a strength higher by 86.6% and a breaking extension lower by 70.2% compared to the copper wire, while its strain sensitivity in the workable strain range is not affected by either the yarn manufacturing process or the existence of staple fibers. The vortex core-spun yarn containing a metal wire could be a promising candidate for the conductive tracks of wearable electronics due to its improved structure, durability, and comfort. [ABSTRACT FROM AUTHOR]

The tangentially injected swirling tube flow has broad applications in various engineering fields. In the textile industry, the vortex spinning technology, which produces short-staple yarns by means of a tangentially injected swirling airflow, is of great prospect in view of its spinning speed and yarn structure. In this paper, the vortex spinning nozzle is abstracted into a model of concentric tubes of different lengths with tangential injectors. A computational fluid dynamics model is presented to study the effects of some structural parameters on the swirling flow generated in this tube system. The particle image velocimetry (PIV) technique is adopted to measure the flow field. Due to the difficulty in duplicating the Mach number, Reynolds numbers are matched between the tube model and prototype in the PIV experiment. Despite the discrepancy between the velocity values provided by the numerical simulation and experiment due to the compressibility effects not being reproduced in the PIV measurement, a comparative analysis concludes that qualitatively matched results on the flow pattern and effects of the structural parameters are obtained by the numerical simulation and PIV measurement. [ABSTRACT FROM AUTHOR]