| Rotor spinning is a kind of air spinning, which is most mature and widely used method in many new methods of spinning technology. The air plays an important role in the spinning progress. Many scholars at home and abroad conducted many experiential studies on spinning technologies of rotor spinning machine, which includes rotor speed, combing roller speed and negative pressure etc. But researches on the characteristics of the internal flow field and fibers’ motion in the rotor cup are not enough. The two factors have a great influence on the quality of the finished yarn, the spinning efficiency, the range of adaptive fibers and so on, so it is the foundation of developing high-performance rotor spinning machines.In this paper, firstly, the pressure equation in the rotation flow field are got by the Euler balance equation. Then the fiber are replaced by the fiber particle. The movement and force are got according to the force analysis of particle on the slide wall. The particle motion equation effected by the slide wall angle and the common angle range of slide wall in theoretical calculation are obtained too. Secondly, the internal flow field model based on the type rotor unit of one textile company in Zhejiang province. Then the characteristics of the internal air flow by the numerical simulation are shown, including the distribution of the air velocity and pressure.The change of flow parameters within the transport channel and the rotor influence on on fiber movement are analyzed. Thirdly, the fiber are replaced by the fiber particle. Then fiber-air two phase flow in a rotor cup are simulated by the Euler model to get the distribution and movement of the fiber particle flow phase. At the same time, the influence of different rotor speed, slide wall angle, transport channel structure and degree on the distribution of fiber particles are analyzed. Finally, rotor, channel, negative pressure cavity and other key parts are made into transparent. The experimental platform are set up to study the fiber characteristics in the transport channel and rotor using the high-speed photography technology. What’s more, the results of the numerical simulation are compared with the experiment characteristic.Through the numerical simulation and experiment, the following conclusions are concluded:1. The pressure inside the rotor is negative, and it is related to the distance from the central axis. The air velocity is increasing in the channel and there is a high speed vortex in the channelexit. The airflow rotates with the rotor when it flows into the cup through the transport channel,and they intersect at the channel exit after flowing a round, turbulence in concurrent region is strongest.2. Fiber head bends in accordance with rotation direction of rotor after going into the cup,and moves to the groove along the slide wall, the fiber clings to the groove with the rotating of rotor. The surface type of the fiber phase distribution in the slide wall is like slop pattern. The length of fiber ring in the groove is increasing constantly. Tiny changes of the slide wall angle has little influence on the fiber flow state, it is about 70° general.3. The rotor speed has no effect on the airflow parameters in the transport channel and the center of the rotor(less than 12 mm space from the axis of the rotor), but it has a greater influence on the airflow state near the rotating wall, such as airflow velocity and pressure(less than 6mm space from the rotating wall). The air velocity increased with the increasing rotor speed at the same location.4. The angle of the transport channel affects the direction of the fiber flow and the position of touch points of fibers on the slide wall, the best angle ranges is from 32° to 37°. Under the same working conditions, the static pressure and airflow velocity at the exit are same in different converging degree channels, but they are inversely proportional to the converging degree at the entrance. |
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