The Study Of Three-Dimensional Flow Field In Air-Jet Vortex Spinning Nozzle And The Motion Of Fiber

Air jet vortex spinning is a new spinning technology which uses high-speed rotating airflow. In addition to the yarn strength slightly lower than ring spinning yarn, other yarn properties are better than that of ring spun yarn. Nozzle parameters affect the airflow characteristics, thus affect the fiber motion, and consequently influence to the air-jet vortex yarn structure and yarn quality. This study studies the flow field in air jet vortex nozzle, and simulats the fiber motion in the nozzle. The study is beneficial to find the principle of air jet vortex spinning,to improve yarn quality, and to explore the yarn performance in specific nozzle parameters.Firstly, fluent6.3softwwere was adopted to simulate three spray angles of nozzle jet vortex, And got the internal flow velocity field of the nozzle. Simulation results show that, the rotating characteristics of the air in the twisting chamber were very obvious. With the spray angle increased, the tangential velocity and radial velocity increased, but the axial velocity was decreased. Larger tangential velocity and radial velocity are beneficial to the separation of the fiber and the yarn twisting. Large spray angle will lead to better yarn quality.Secondly, we used air jet vortex nozzles to do single factor experiments successfully. By changing spray angle, the distance between yarn guide needle and the hollow tube, hollow cone angle and the pressure in the spray, comparison tests were completed. The yarn performances were also tested, so the nozzle parameters influence on yarn properties were discussed.Finally, fiber/air mathematical model was established. The data of the airflow velocity of80°in spray angle was used in the model, and the motion equations of fiber are solved. The fiber motion in the airflow field of the nozzle was simulated. The results showed that, in the nozzle centre plane and near the orifice,wobble motion characteristic of the end fiber was very obvious. End fiber can separate from the fiber bundle completely at one moment. After the fiber enters the hollow tube, its wobble motion is not obvious.