Research On Reducing Ring Spinning Hairiness With Swirling Nozzle

Swirling nozzle is an installation which uses special internal structure to change compressed air into rotation airflow to reduce hairiness. Its structure determines the motion state of airflow. The swirling nozzle which was devised by our research team could reduce yarn hairiness in a certain spinning condition, and the breaking strength and fineness were dropped. So the interior structure of swirling nozzle still needs improving. In this paper, we designed a new swirling nozzle which was optimized and improved for the prior cyclone. The paper mainly includes four parts as follows.First of all, we discussed the trajectory cross-sectional shape of the nozzle and designed oval cross-sectional nozzle on the basis of previous research. The results showed that: when the pressure was 0.07 to 0.25MPa, the hairiness of 3 mm and more were reduced by pressure with oval cross-sectional nozzle. But the hairiness was increased while the pressure was blow 0.07MPa. Yarn's breaking strength was lower than traditional spinning and spinning with circular cross-sectional nozzle all the time. Yarn's unevenness was receded, but the neps and nubs were more compared with traditional spinning and circular cross-sectional nozzle. In a word, the oval cross-sectional nozzle could improve yarn's quality, but it was not better than the circular one.Secondly, we optimized the airway angle and designed ten nozzles with five sharp angles (40°,50°,60°,70°,80°)and five obtuse angles (100°,110°,120°,130°,140°). The airway of sharp angle nozzles was head to the direction of spinning triangular zone while the obtuse ones were towards the yarn guide hook. The nozzles were fitted on the spinning frame and the yarns were tested. The results showed that: spinning with the sharp angle nozzles were better than with the obtuse ones under the same spinning parameters. The properties including the hairiness number, breaking strength and unevenness of yarn by nozzle with 40°were better than the other sharp ones or 90 angle nozzle. And the hairiness number of yarn by 100°nozzle were not better than the 90 angle ones. So it could be more proper to design the airway of swirling nozzle to be 40°for proving yarn's qualities.Thirdly, we optimized spinning process parameters by the nozzle with circular cross-section and 40°airway. Results showed that the four most optimal process parameters of spinning were 0.2MPa (pressure), 5.5cm (mounting distance), 370 (twist), 8000r/min (spindle speed). Compared with traditional ring spinning, the hairiness of 3mm and more were reduced 89.6%, the hairiness of more than 3mm were reduced 100%, the breaking strength was improved 12.4%, the yarn unevenness was receded 27.5% .Finally, we simulated the airflow of internal nozzle by CFD. It was found that the airflow all flew towards front jaw with the circular cross-section and 40°airway nozzle. The axial velocity was larger than tangential and radial velocity. The velocity distribution of airflow on every section was different. The results showed that the velocity on the center section reached the maximum and died down near to the front jaw direction.