Modeling the airflow field of vortex spinning

Abstract

Vortex spinning technology adopts a high-speed swirling airflow to rotate the fibers with open-ends to form yarn with real twists. The airflow behavior within the nozzle has a great effect on the yarn-formation process. In this study, a three-dimensional calculation nozzle model and corresponding three-dimensional airflow region model were established to enable the numerical calculation; airflow behavior—pressure, velocity, and the turbulent airflow field, and the streamline of airflow—was 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 airflow diffusion and convection in the nozzle, the Realizable k- ε turbulence model with wall function was adopted to conduct the calculation. Dynamic and static pressure values were obtained by numerical analysis to predict the action of the inner surface of nozzle and the wall resistance on the high-speed swirling airflow. The numerical simulation of dynamic airflow behavior can generate great insight into the details of airflow behavior and its distribution characteristics, and is helpful for understanding the spinning mechanism and promoting optimization of the spinning process.

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

“…41,42 The realizable kÀe model has been proved to have significant improvements over the standard kÀe model in handling flows with strong streamline curvature, vortices, and rotations. [43][44][45] The turbulent field was mainly characterized by turbulent kinetic energy and turbulent viscosity, by comparing the two, Shang et al 37 demonstrated that the flow field was more disordered in steady spinning stage than in the initial spinning stage. Shang et al 44 suggested that the presence of the cone body had influenced the dissipation and rupture of the turbulent vortex.…”

“…[43][44][45] The turbulent field was mainly characterized by turbulent kinetic energy and turbulent viscosity, by comparing the two, Shang et al 37 demonstrated that the flow field was more disordered in steady spinning stage than in the initial spinning stage. Shang et al 44 suggested that the presence of the cone body had influenced the dissipation and rupture of the turbulent vortex. High velocity air flow is also compressible.…”

Numerical simulation and experimental research of fiber motion in vortex spinning

“…where, j is the jth triangular element; A, B, and C are the three nodes of a triangular unit; / A , / B , and / C are the velocity potentials of the air-flow field at A, B, and C nodes, respectively; x, y, and z are coordinates in rectangular coordinates; n is the unit normal vector. By solving equation (22), the velocity potential gradient of element j can be obtained, and other elements are similarly found.…”

“…), but also at the influence of air flow on fiber, the important air-flow fields that affect the fiber were analyzed already in a previous research study. 22 In this article, we provide details of a continuation of previous research, and our main focus is on the characteristics and motion of the fiber.…”

“…Thus, these extremely small fibers need to be separated from the air-flow field for research and analysis. In our previous results, 22 we looked not only at the unsteady air flow (including the velocity field, the turbulent kinetic energy, and the trajectory of the air flow, etc. ), but also at the influence of air flow on fiber, the important air-flow fields that affect the fiber were analyzed already in a previous research study.…”