Abstract:

In order to explore flow field characteristics in the rotor spinning unit and the influence of different rotor speeds on the quality of composite yarn, a 3-D model of the spinning unit and numerical simulation of the flow field were studied by Ansys software, including analysis of pressure and velocity distribution characteristics within the spinning channel. Rotor spun composite yarns were produced at different rotor speeds. The results show that under the same conditions, the minimum static pressure within the directing tube can be dropped to  -9.8 kPa, and the negative pressure in the rotor is around 9 kPa. A small number of high pressure zones exist in the outlet of the transfer channel and rotor slip plane. The speed of airstream accelerates from the transfer channel inlet to the outlet with the decrease of the pipe diameter, and reaches the largest value of 386 m/s at the outlet. The accelerated airstream impacts to the rotor slip plane from the transfer channel outlet, and is divided into two strands of the opposite direction airflows, and the airflows move as a circular motion along the outlet of the filament guide tube. Experimental results demonstrate that as the rotor speed increases, the airflow velocity increases, the static pressure decreases, the breaking strength and evenness of composite yarn increase, and the breaking elongation and hairiness of composite yarn decrease.

Key words: rotor spining, composite yarn, airflow characteristic, yarn quality, mathematical simulation