基于Ω漩涡识别方法探究转杯凝聚槽漩涡对纺纱质量的影响OA北大核心CSTPCD

Rotor spinning utilizes airflow as a driving force to achieve operations such as fiber transport and aggregation.The characteristics of the airflow field during the spinning process directly impact the spinning results.The article employs simulation software to model the movement of airflow within the rotor,investigating the correlation between the airflow field inside the rotor and the quality of yarns.The research provides valuable guidance for enhancing the structure of rotor spinning. To more accurately identify and analyze the vortex patterns within the complex and dynamic flow field inside the rotor in air-jet spinning,a vortex identification method combining the Ω vortex determination criteria with image processing was proposed.The method involved analyzing the flow field within the rotor obtained through simulation with FLUENT.,provideing insights into the number and area of vortexes in the condensation slot.The properties of these vortexes were further discussed.The simulation analysis results indicate that the distribution of static pressure values on the rotor's surface is uneven,leading to varying pressures at different locations across the rotor.Within the fiber delivery channel,the static pressure gradually increases to-7 kPa as the channel diameter decreases.Notably,there is a substantial static pressure gradient change on the wall surface near the channel outlet.Inside the rotor,the fastest airflow velocity observed at the location of the condensation slot forms a circular ring of high velocity.The middle section of the rotor experiences slower airflow velocities,extending to the entrance of the yarn guide tube.On the side of the rotor closer to the fiber delivery channel,there is a long strip-like region with higher airflow velocity.By observing the vortexes identified using the Ω method,it is evident that this approach has a superior ability to capture vortexes within the plane.It not only captures the larger vortexes displayed in streamline plots but also effectively captures smaller vortexes within the condensation slot that may not be discernible in streamline plots.Additionally,vortexes within the condensation slot are primarily concentrated at the outlet of the fiber delivery channel and at the intersection of airflow behind it.This phenomenon arises due to the relatively complex airflow movement in these two positions.As the rotational speed increases,the area of smaller vortexes inside the rotor's condensation slot also increases.The vortex area increases from 14.1 mm2 to 18.5 mm2,and the yarn coefficient of variation increases from from 15.33 to 15.99,resulting in decreased overall yarn uniformity.The increase in rotational speed also leads to an increase in the number of coarse and fine nodes on the yarn,resulting in a decline in yarn quality.When the rotor diameter is increased,the area of vortexes within the rotor's condensation slot decreases.The vortex area reduces from 15.6 mm2 to 10.7 mm2,representing a reduction of 31.4%.The coefficient of variation decreases from 15.53 to 15.02,indicating enhanced yarn uniformity and improved spinning results. The Ω vortex identification method exhibits excellent capturing capability for vortexes on the plane of the condensation slot.After undergoing image processing,this method allows for the quantitative analysis of the vortex patterns within the internal airflow field of the spinning cup.Vortexes within the condensation slot are mainly concentrated at the outlet of the fiber delivery channel and at the intersection of airflow behind it.Lowering the spinning cup's rotational speed and increasing its diameter can enhance the quality of the yarn.