Numerical simulation of dynamic pressures on a novel drafting system and experimental study on yarn properties based on friction fields

Abstract

The friction fields of a novel drafting device based on the ring spinning frame are investigated in terms of numerical simulation and experimental studies. In numerical simulation, the results demonstrate that the dynamic pressure distribution in the drafting zone is presented in the form of wave undulation in the main drafting zone. Besides this, the pressure peak greatly increases close to the front nip. The effect of different spacers and middle roller speeds on the pressure distribution was also simulated, which indicates that the dynamic pressure decreases strictly with increasing spacer size, while at middle roller speeds of 0.18 rad/s and 0.26 rad/s the pressure distributions only show a significant difference at the pins nip and not throughout the drafting zone. For experimental studies, the friction fields of the novel drafting device were tested with different spacers. The peaks of the friction field decrease with the increasing spacing in the main drafting zone. The friction force shows a wavy undulation in the direction of the middle roller nip to the front roller nip, and there is also a great increase in the peak of the friction force near the front roller nip. Analysis of the properties of the three yarns spun by the novel draft device under different spacers shows that changing the spacer affects the friction forces of the drafting zone and has a significant effect on the yarn evenness, imperfections, and strength, but not on the hairiness.

Investigation into novel drafting systems on ring spinning frame for improving yarn properties

“…In the spinning process, neps are mainly caused by the entanglement of fiber masses and yarns. 24 Both the N–A and N–B devices are simple in construction and have generally identical drafting parts. This means that there is little difference in the improvement of neps +200% between the two devices.…”

“…The friction field is improved by the curved drafting channel, thereby regulating the movement of the fiber bundles. 23,24…”

“…In a previous study of the novel drafting device, it was observed that the friction field was presented in the form of wave undulation in the main drafting zone, due to the design of four effective control zones in the drafting zone. 23,24 Furthermore, two types of top pins have been designed to spin yarns, which demonstrates that the differences in the friction fields caused by the different top pins significantly affected yarn properties. 4 Therefore, attention needs to be paid to the fact that structures of the pins in the curved drafting channel are closely related to the quality of yarns.…”

“…Based on the afore-mentioned research, a novel drafting system based on a ring spinning frame has been proposed by Quan and colleagues 4,23,24 In the preliminary study, theoretical and experimental investigations of the new device were carried out. In the theoretical aspect, the friction fields in the drafting zone were simulated and the differences in the acceleration points caused by different friction distributions were analysed.…”

Pressure distribution in the drafting zone measured by film pressure sensors

“…Quan et al. 16,17 numerically simulated the static pressure distribution in the curved path of drafted strands with a simplified finite element model, but the results were theoretical and not verified experimentally.…”