Research On The Flow Field Of Weft Insertion And Structure Optimization Of The Auxiliary Nozzle In An Air-Jet Loom

The air-jet loom with profiled reed is widely used at home and abroad. As the basic component, the auxiliary nozzle and profiled reed are essential for air-jet looms and the correlative research is relatively rare. Therefore, research on the weft insertion process of the auxiliary nozzle in air-jet looms is meaningful. Based on the current research by the group, it makes some conclusions on the study about the flow field’s characteristic and the structure of the auxiliary nozzle with the way of using the CFD software and experimental platform.To study the single-hole auxiliary nozzle which is the most frequently used nozzle, the comprehensive analysis on the velocity distribution of the symmetrical plane, the flow field centerline and different sections is made by the combination way of numerical simulation and experimental test. The result of the analysis better describes the characteristic of the flow field. What’s more, it proves the rationality and accuracy by using Fluent to do numerical simulation.On the base of the feasibility in using Fluent, the optimization analysis is obtained according to the orifice feature of the single-hole auxiliary nozzle, the 2-hole auxiliary nozzle and the rectangle-hole auxiliary nozzle. Results show that the single-hole auxiliary nozzle with a 6 degree angle performs best; the optimal models of 2-hole auxiliary nozzle are obtained under different corresponding indicators; the rectangle-hole auxiliary nozzle with a length-width ratio of 3.3 is best and the universality of this ratio is proved.The study on the combination of flow field which established by the auxiliary nozzle, the profiled reed and the shed, is made to accurately explain the characteristic of the flow field. By the analysis of velocity distribution of the flow field centerline as well as the structure parameters of the combination of flow field that include the underlip obliquity of profiled reed and the distance between auxiliary nozzle and profiled reed, the optimal process parameters under different supply pressure are obtained.Experimental study on the air drag force of weft yarns is carried out by considering the participation of weft yarns in actual weft insertion. According to the results, the characteristic of flow field and the features of different auxiliary nozzles are further described from the perspective of the air drag force of weft yarns. At the same time, the significance of the structure optimization of auxiliary nozzles is proved in some measure.The conclusions based on the research methods of the combination of numerical simulation and experimental test provide the references for the actual production of auxiliary nozzles and the improvement of the weft insertion process.