辅助喷嘴结构对喷气织机异形筘内合成流场特征的影响

为提高喷气织机引纬系统的引纬速度和稳定性,采用雷诺时均方程中的k-ε双方程湍流模型分别对单圆孔、正三角形孔和星形孔3种不同的典型喷嘴与异形筘的合成流场进行模拟仿真,得到在0.2~0.4 MPa供气压力下不同辅助喷嘴间距合成流场中心轴线气流速度和流场速度云图。结果表明:当压力相同时,正三角形孔辅助喷嘴合成流场中心轴线气流速度最高,对纱线牵引力最大;星形孔辅助喷嘴合成流场中心轴线气流速度变化幅度最小,引纬稳定性最好;单圆孔辅助喷嘴中心轴线气流速度波动最大,间距超过70 mm,不适合引纬;在全幅织物接力引纬时,各组喷嘴射流的喷射时间互相衔接,喷嘴间距不宜太长。

Effect of structural parameter of relay nozzles on characteristics of flow field in profiled reed of air jet loom

In order to improve the speed and stability of weft insertion system of air-jet looms, the k-ε expression in the Reynolds time average equation was used to simulate the resultant flow field of three different relay nozzles,i.e. a single circular hole, a regular triangular hole and a star-shaped hole,in the profiled reed. Under the air supply pressure of 0.2-0.4 MPa and the different auxiliary spray spacing, the combined flow field was simulated revealing the jet velocity and velocity nephogram along the central axis of the flow field. The results show that when the pressure is the same, the velocity of the central axis of the resultant flow field of the triangle hole relay nozzle is the highest, and it has the largest traction force on the yarn; the velocity of the central axis of the resultant flow field of the star-shaped hole relay nozzle is the smallest, and the weft insertion stability is the best. It was also found that the velocity fluctuation of the central axis of the single circular hole relay nozzle is the largest, and the spacing is more than 70 mm, which is not suitable for weft insertion. Several groups of relay nozzles are used for the width of the whole fabric, and the action timing of each group of nozzles were synchronized. Because the useful jet length is not long, the interval between the nozzles should not be too long in order to realize the relay weft insertion.