气流引纬主喷嘴内气流速度与纬纱间摩擦因数的关系

Relationship between friction coefficients of weft yarns and velocity of air-flow in main nozzle during weft insertion

喷气织机在引纬过程中纬纱所受牵引力大小与纬纱和气流的相对速度、气流密度、纬纱直径、引纬长度、气流与纬纱的摩擦因数等因素有关。其中,不同相对速度下气流与纬纱间的摩擦因数不同,由于主喷嘴内部气流速度与密度难以进行实际测量,故对其进行数值模拟,结合对纬纱牵引力的实验测试,反推出在不同相对速度下气流与纬纱的摩擦因数,并对实验数据进行分析。结果表明:在一定的供气压力范围内摩擦因数随相对速度的增大而减小。通过对摩擦因数和相对速度进行拟合,可以求出任意相对速度下的摩擦因数。这个结果对准确计算纬纱牵引力及推算纬纱飞行速度均有一定的指导意义。

The value of weft insertion force during the insertion process of an air-jet loom is related to the relative velocity between the weft and airflow, density of the airflow, diameter of the weft, insertion length and friction coefficient of the yarn. The friction coefficient of the yarn is a variable under different relative velocities. As the velocity and desity of air-flow in main nozzle are hard to measure, in order to deduce the relation, a simulation of air-flow velocity and density and a measurement of the insertion force are made. The results indicate that the friction coefficients of weft yarns decreased with the increasing of relative velocity in a certain range of pressure. By fitting the coefficients to the relative velocity, the values of coefficients under any relative velocity can be worked out. The results have directive significance for the accurate calculation of weft insertion force and the deduction of weft flight speed.