Modeling the airflow field of vortex spinning

Vortex spinning technology adopts high speed swirling air-flow to rotate the fibers with open-ends to form the yarn with real twists. The air-flow behavior within the nozzle has a great effect on yarn formation process. In this study, the three-dimensional calculation nozzle model and the corresponding three-dimensional air-flow region model were established to proceed the numerical calculation; the air-flow behavior: the pressure, the velocity and the turbulent air-flow field, as well as the streamline of air-flow, were investigated in the presence of fiber bundles within the vortex spinning nozzle. Hybrid hexahedral/tetrahedral control volumes were utilized to mesh the grids in the calculation region. To consider air-flow diffusion and convection in the nozzle, the Realizable k-ε turbulence model with wall function was adopted to conduct the calculation. The dynamic pressure and the static pressure were obtained by numerical analysis to predict the action of the inner surface of nozzle and the wall resistance on the high speed swirling air-flow. The numerical simulation of dynamic air-flow behavior can generate great insight into the details of air-flow behavior and its distribution characteristics, as well as be conducive to understand the spinning mechanism and promote the optimization of spinning process.