Influences of the air inlet and yarn-loading slit on the performance of an air-twist nozzle

Abstract

An air-twist nozzle has an air inlet and yarn channel with a yarn-loading slit. The nozzle was investigated by changing the width and length of the air inlet and by modifying the yarn-loading slit using computational fluid dynamics. The airflow vorticity, mass flow rate, and velocities of the air-twist nozzle were evaluated to analyze the influences of the air inlet and yarn-loading slit. The velocity and vorticity were high when the width and length of the air inlet were 0.2 and 0.1 mm, while the diameter and length of the yarn channel were fixed at 1 and 3.5 mm, respectively. The air inlet was divided into two and three small rectangular air inlet holes to increase the velocity and vorticity. The velocity and vorticity were high but not uniform at the yarn channel. Dividing the air inlet increased the velocity but disturbed the air-twisting process; therefore, the air inlet without dividing was selected for further computations. The influence of the yarn-loading slit on the air-twist nozzle flowfield was observed to improve the performance of the nozzle by changing and removing the slit. The velocity, vorticity, and mass flow rate were improved significantly when the yarn-loading slit was removed. The air-twist nozzle with the removed yarn-loading slit was fabricated as a prototype for testing. The air-twist nozzle was compared with the existing air-twist nozzles under identical conditions. The test results showed that the developed air-twist nozzle with removed yarn-loading slit had better performance than the existing nozzles.