【作者】 张勇；

【导师】 曾泳春；

【作者基本信息】 东华大学 ， 纺织工程， 2013， 硕士

【摘要】 喷气涡流纺纱是利用高速旋转气流进行纺纱的新型纺纱技术,除纱线强力比环锭纱稍低外,其他纱线特性均优于环锭纱。喷嘴参数值的变化影响着喷嘴中气流的流动特征,从而影响纤维在喷嘴中的运动状况,而纤维在喷嘴中的运动又影响了喷气涡流纱的结构,进而影响纱的最终性能。本文对喷气涡流喷嘴内部流场进行研究,并模拟纤维在喷嘴中的运动,有利于找寻喷气涡流纺的成纱原理,提高产品质量,并且可以探究特定喷嘴参数下的纱线性能。首先,采用fluent6.3软件对三种喷孔角度的喷漆涡流喷嘴进行三维数值模拟,得到各自喷嘴内部的气流场。模拟结果显示各喷嘴加捻室中的气流旋转特征非常明显,并随着喷孔角度的增大,A-A截面的切向速度和径向速度增大,而轴向速度减小。较大的切向速度和径向速度有利于纱线的加捻和纤维的分离,故选择喷气涡流纺喷嘴时,为更容易纺纱和提高纱线质量,喷孔角度应适当大些。其次,用喷气涡流喷嘴进行相应的单因子纺纱实验,即通过改变喷孔角度、导纱针到空心管的距离、空心管锥角以及气压等参数进行对比试验,对纱线的性能进行测试,通过测试结果探讨这几种喷嘴参数对纱线性能的影响。最后,建立纤维/气流的珠-杆数学模型,对模型进行受力分析,建立运动方程,并提取80°喷孔角度喷嘴模型的气流速度数据,求解纤维运动方程,对纤维在喷气涡流纺喷嘴气流场中的运动轨迹进行追踪。结果显示,在喷嘴中心面上,喷孔附近,纤维尾端摆动的特性非常明显,某一时刻,纤维尾端可以完全从纤维束中分离出来,进入空心管后的纤维段,摆动不明显。更多还原

【Abstract】 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.更多还原