Numerical simulation and experimental research of fiber motion in vortex spinning

Abstract

The application of high speed air flow in the textile field represents the frontier development direction in this field. However, the coupling mechanism between air flow and fiber is extremely complicated which greatly limits the development and application of new textile technologies. For this reason, this research study is intended to focus on the common cutting-edge basic scientific problem of the air-flow-fiber coupling mechanism, the vortex spinning technology is taken as a breakthrough point for research. Three-dimensional numerical models of air flow in vortex spinning nozzle and a free-end fiber were established. The hybrid grids including the structured hexahedral grids and the unstructured tetrahedral grids were used to divide the air-flow computational region, the realizable κ- ε model was used to solve the turbulent characteristics of air flow, and the wall function method was used to solve the air flow in the near wall region. The displacement and deformation of a single free-end fiber under the action of the air-flow force was solved by the second-order nonlinear double asymptotic method and interpolation method. The dynamic twist process of a free-end fiber was simulated in three-dimensional space by taking into account the fiber characteristics, such as straightening, bending, and torsion. In addition, a high magnification microscope was used to observe the free-end fiber motion during the spinning process. The results show that the numerical simulation is consistent with the experimental observation, proving that dynamic numerical simulation can solve difficult problems in the unobserved dynamic twisting process, and this deepens the understanding of the spinning mechanism in vortex spinning.

Progress of air flow field and fiber motion analysis in textile manufacturing process: a review

“…The main function of the vortex field in the textile process is twisting yarns, which is used in vortex spinning 1 and rotor spinning, 2 but some tiny vortices are not conducive for yarn orientation. The jet field has critical functions in fiber web forming and guiding yarn movement, and is widely used in air jet looms weft insertion, 3 electrostatic spinning, 4 melt blown spinning, 5 and spunbond processes.…”

Fiber movement during twisting in air vortex spinning

“…Shang et al 1 verified that the turbulence generated during the normal spinning process is much more pronounced than at the beginning of spinning by analyzing the three-dimensional numerical simulation of airflow characteristics, which is conducive to the stabilization of the spinning process and the improvement of yarn strength. Shang et al 2 developed a three-dimensional numerical model of airflow within a vortex spinning nozzle and a free-end fiber, utilized structured hexahedral meshes and unstructured tetrahedral structures to delineate the computational region of the airflow and verified the importance of dynamic numerical simulation in solving the unobservable dynamic torsion process by taking into account the physical properties of the fiber. Pei and He 3 utilized a charge-coupled device in conjunction with an industrial endoscope to observe the formation process of a copper wire core yarn and theoretically demonstrated that this method can be applied to other textile manufacturing processes.…”