| The air-jet loom adopts the weft insertion mode of combining the main nozzle,auxiliary nozzle,profiled reed groove and extended nozzle.The high-speed jet is injected by the nozzle to form the airflow field,and the weft is conveyed through the shuttle.At present,the research mainly focuses on the main nozzle,auxiliary nozzle and profiled reed groove,but few studies have been done on the extended nozzle at the end of weft insertion system.With the increasing variety of textiles,the requirement for air-jet weaving is higher.For fiber bundles,the aggregation between fibers is relatively weak and the weaving is more difficult.In this paper,the extended nozzle at the end of weft insertion system is the main research object.The airflow field at the end of weft insertion system is simulated,the airflow field characteristics in the extended nozzle are analyzed,and the structure of the extended nozzle is optimized.Then the airflow-fiber bundles coupling in the extended nozzle is simulated,and the motion characteristics of free fiber bundles in the extended nozzle are analyzed.Finally,an experimental platform is built to study the movement of free fibre bundles in the extended nozzle,and the comparison between the experimental results and simulation results is carried out.It provides some theoretical support for improving the performance of air-jet looms.This study is mainly carried out in the following aspects:(1)The airflow field of the end of weft insertion is simulated,the airflow field in the extended nozzle is analyzed,and the structure of the extended nozzle is optimized.The optimum position of the extended nozzle in the weft insertion system,the position of the extended nozzle inlet and the injection angle of the extended nozzle inlet are determined by studying the modeling of the extended nozzle,the modeling of the airflow field at the end of weft insertion,the setting of boundary conditions,numerical simulation and experimental verification.(2)Numerical simulation of airflow-fiber bundle coupling in extended nozzle.The solution method of airflow-fiber bundles coupling is studied.The constitutiveequation of the fiber bundles and the model of airflow-fiber bundles coupling are established.The motion of a single fiber and fiber bundles in the extended nozzle is numerically simulated and the motion characteristics are analyzed.(3)Experimental study on airflow-fiber bundles coupling.The motion characteristics of fiber bundles in extended nozzle are studied by means of high-speed photography experiment.The radial displacement,aggregation and axial velocity of fiber bundles are analyzed.The comparison between the experimental results and simulation results is carried out. |
PDF Full Text Request