喷气涡流纺喷嘴内气流流动的二维数值模拟

 为探讨喷嘴内部气流流动特征对纤维加捻成纱的作用,建立计算流体动力学(CFD)模型,对喷气涡流纺喷嘴中的气流流动进行二维数值模拟,并根据计算结果分析喷嘴内高速气流的速度场和压力场分布。模拟结果表明:气流的最大速度可达超音速,由于切向速度所产生的离心力和加捻作用,纤维的尾端从纤维束中分离出来,并旋转加捻到纤维束上,形成具有真捻的纱线;喷嘴入口区域的压力小于外界气压,这有利于由前罗拉钳口处输出的纤维束吸入喷嘴。研究还表明CFD技术是研究喷气涡流纺喷嘴内气流流动的重要手段。

Two-dimensional numerical simulation of air flow in an air-vortex spinning nozzle

To investigate the effect of air flow in an air?-vortex spinning nozzle on yarn forming through twisting fiber strands,a computational fluid dynamics(CFD) model has been developed to simulate the air flow characteristics in an air-vortex spinning nozzle.Two-dimensional simulation and standard k-ε turbulence model is used.The computational results show that the velocities in the nozzle are transonic.Velocity and static pressure distributions in the nozzle are presented and analyzed.Due to the centrifugal and twisting forces generated by tangential velocity,the rear ends of the fibers are separated from the fiber strand and spread out.Then they helically wound round the fiber strand to form a real-twisted yarn.In the upstream of the jet orifices,the pressures are lower than the atmosphere pressure,which is helpful for sucking the fiber strand coming out from the front roller nip into the nozzle.This work shows that CFD technique can provide a better understanding of the behavior of the high speed air flow in the air-vortex spinning nozzle.