The Research On Coupling Simulation Of The Flight Attitude Of Single Fiber In Jet Flow

The air-jet loom is a shuttleless loom that draws the weft yarn into the profile reed slot by using a high-speed jet stream.The main nozzle plays a crucial role in inserting the weft yarn into the profile reed,and the flow field and the yarn are fluid-structure coupled The athletic research on the success of jet weft or study the impact of various factors have a very important position.At present,most of the literatures at home and abroad only involve the use of CFD simulation to obtain the main nozzle airflow distribution characteristics to study the influence of airflow velocity and pressure on the flight speed of the yarn,as well as the influence of the roughness of the hairiness on the yarn physical surface,Flight impact study,or to improve the structure of the main nozzle of the air-jet loom to improve the air velocity to obtain higher airflow traction and faster yarn flight speed,finishing many scholars found that the role of airflow distribution Airflow traction concept Under,do not think that in essence to explore the yarn in the flow field in the movement of attitude characteristics.In this paper,the following research is carried out on the RFJA10 weft loom weft insertion system.A CFD numerical simulation data based on the main nozzle was proposed.The coupled numerical algorithm proposed in this paper was used to simulate the yarn attitude change and the flight speed change at each time step by Abaqus.Due to the self-programming and uniqueness of the algorithm and software,the algorithm and software are firstly verified.The changes of the up-and-down wiggling posture and the take-off and landing flight of the weft yarn during the weft insertion start-up are studied emphatically.The combination of field and solid field numerical simulation provides a good theory-based working condition for the actual operation of the weft insertion mechanism of air-jet weaving loom.In this paper,CFD computational fluid dynamics(CFD)method is used firstly to simulate the flow field of the main nozzle with RNG k-ε turbulence model and density-based coupled implicit implicit solver.And from the point of view of the accuracy of the experimental data,a mass flow experiment was conducted to verify the correctness and reliability of the simulation data.Based on this,the rod unit-chain three-dimensional structure was proposed for the yarn modeling in Abaqus.With the high degree of coincidence and small error,we can observe the three-dimensional The attitude changes.By simulating the start-up phase and the take-off phase of jet weft insertion and the comparison of the images captured by the high-speed photography experimental platform,it can be concluded that the simulation results are in good agreement with the jet weft insertion on the air jet loom.The research results show that the variation of the attitude of the yarn in the most important part of the weft insertion of the main nozzle in the airflow field.Summarizing the Yarn At the preparation stage of weft insertion,the yarns have the rules of controllability at different lengths under the action of low frequent spraying,and found that the weft insertion of yarns under different lengths will have different attitude changes,Although it has no influence on the process of weft insertion into profiled reed,it can provide a more accurate theoretical condition of operating conditions of air-jet looms and the self-compiled software can simulate different types of yarn by adjusting yarn physical parameters Of yarn weaving,which on the domestic production of loom manufacturers have high utilization rate,and can improve weft insertion efficiency to achieve further economic development.Through the weft insertion start-up stage studied in this paper,the jet weft insertion also includes that the yarn is completed by flight under the action of a shaped reed runner groove and an auxiliary jet nozzle structure,and temporarily aground during the auxiliary jetting stage due to experimental conditions,but hopefully,The paper proves that the numerical algorithm and software of the self-made software can be used as a reference for the researches on similar topics,hoping to provide some help for the theoretical research and development of air-jet looms.