“…To ensure better mesh quality, cell size and optimum cell size have to be controlled to suit standard requirements. 3,10 Figure 3.Mesh topology and name selections of the three-dimensional model.…”
Section: Theoretical Model Constructionmentioning
confidence: 99%
“…These default values are determined from the experiments for fundamental turbulent shear flows, including homogeneous shear flows and decaying isotropic grid turbulence. 3,10 Table 3 shows the values of the constants.…”
Section: Governing Equations and Turbulence Modelmentioning
confidence: 99%
“…The standard k-" two-equation turbulence model only applies where the flow is fully turbulent, and the effects of molecular viscosity are negligible; hence, making it valid for fully turbulent flows with high Reynolds numbers. 3,20…”
Section: Governing Equations and Turbulence Modelmentioning
confidence: 99%
“…Numerical analysis is a valuable tool in this regard; studies of high-speed airflow in open-end rotor spinning, air-jet texture, air filtration, and internal material flow studies have capitalized on the use of computational methods. 1–7 Internal and external airflows and air–particle interaction studies have been widely analyzed using computational simulation by the numerical methods approach. 1,7–10 Recent studies on airflow in rotor spinning show a significant correlation between the airflow characteristics, the spinning parameters, and consequently the yarn quality characteristics.…”
mentioning
confidence: 99%
“…Although it is still a complex phenomenon to characterize internal airflows and their influence on the quality of yarn, commendable achievements by current researchers using CFD have inspired our research. 1,[3][4][5][6]11,13 In typical rotor spinning, the opening roller speed, rotor speed, and material processed affect flow characteristics, such as the negative pressure and turbulence strength. The current study presents an air simulation experiment for 3D airflow in a dual-feed rotor spinning unit without material.…”
In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.
“…To ensure better mesh quality, cell size and optimum cell size have to be controlled to suit standard requirements. 3,10 Figure 3.Mesh topology and name selections of the three-dimensional model.…”
Section: Theoretical Model Constructionmentioning
confidence: 99%
“…These default values are determined from the experiments for fundamental turbulent shear flows, including homogeneous shear flows and decaying isotropic grid turbulence. 3,10 Table 3 shows the values of the constants.…”
Section: Governing Equations and Turbulence Modelmentioning
confidence: 99%
“…The standard k-" two-equation turbulence model only applies where the flow is fully turbulent, and the effects of molecular viscosity are negligible; hence, making it valid for fully turbulent flows with high Reynolds numbers. 3,20…”
Section: Governing Equations and Turbulence Modelmentioning
confidence: 99%
“…Numerical analysis is a valuable tool in this regard; studies of high-speed airflow in open-end rotor spinning, air-jet texture, air filtration, and internal material flow studies have capitalized on the use of computational methods. 1–7 Internal and external airflows and air–particle interaction studies have been widely analyzed using computational simulation by the numerical methods approach. 1,7–10 Recent studies on airflow in rotor spinning show a significant correlation between the airflow characteristics, the spinning parameters, and consequently the yarn quality characteristics.…”
mentioning
confidence: 99%
“…Although it is still a complex phenomenon to characterize internal airflows and their influence on the quality of yarn, commendable achievements by current researchers using CFD have inspired our research. 1,[3][4][5][6]11,13 In typical rotor spinning, the opening roller speed, rotor speed, and material processed affect flow characteristics, such as the negative pressure and turbulence strength. The current study presents an air simulation experiment for 3D airflow in a dual-feed rotor spinning unit without material.…”
In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.
The annual demand for fibres continues to rise worldwide. Consequently, more and more fibres must be produced to meet this demand, most of which are melt-spun polymeric man-made fibres. [1] Smooth filaments made of polymers are mainly used for technical applications in industry. For use in clothing or home textiles, for example, a texturing process is used to give the filaments a crimp and thus a feel like that of natural fibres. In this state, they can be processed together with natural fibres and used in textiles. Partially oriented yarns (POY) are of great importance in tex-turing. The yarns are mainly crimped with the help of the so-called false-twist texturing process (FTTP). [2] Since POY accounts for about 60 % of the melt-spun filament yarn produced world-wide, the FTTP is the most important texturing process in the textile industry [3]. In this paper, the main components of false-twist texturing (FTT) machines are explained along with the state of the art and research for each component and its influence on the process. Relevant patents are dis-cussed as well as process optimisation techniques, innovative polymers and yarn types recently used in FTT, followed by a conclusion and an outlook for the process.
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