喷气涡流纺喷嘴中纤维运动的数值模拟

Numerical Simulation of the Fiber Motion in the Nozzle of Murata Vortex Spinning

建立了能够反映柔性纤维物理与力学特征的二维模型,结合任意拉格朗日-欧拉法,求解纤维在喷气涡流纺喷嘴中与气流相互作用的流固耦合问题及纤维与喷嘴壁面的接触问题,数值模拟纤维在喷气涡流纺喷嘴高速气流中的运动与变形.研究表明,在喷嘴内气流的作用下纤维随时间呈现波浪形的螺旋运动,并向下游运动,在此过程中与锭子内壁多次发生接触;纤维尾端在完全进入锭子之前以较大的幅度在喷嘴壁面间进行螺旋回转,从纤维束中分离出来并做包缠运动,使纤维束加上捻度;纤维加捻的强度可以用纤维尾端周期性转动的幅度与频率表示.

A two-dimensional model for describing the physical and mechanical characteristics of a flexible fiber was set up.The arbitrary Lagrangian-Eulerian technique was adopted to solve the fluid-structure interaction between the fiber and the airflow in the Murata Vortex Spinning（MVS）nozzle.The contact problem arising between the fiber and the nozzle wall was also solved and the motion and deformation of the fiber in the airflow inside the MVS nozzle were successfully simulated.The results showed that with the action of the airflow,the fiber showed helical movement with wave shape.During its downstream motion,the fiber contacted the inner wall of the spindle frequently.The trailing end of the fiber whirled within the nozzle wall with great amplitude.The separation and wrapping motion of the fiber took place and twists were inserted into the fiber strand before the trailing end of fiber entered the spindle entirely.The intensity of the twists inserted into the yarn can be evaluated by the amplitude and the frequency of the periodical rotation of the trailing end of the fiber.