Structure Optimization Of The Auxiliary Nozzle In Air-jet Loom Based On 3D Printing

Air-jet loom is gradually developing in the direction of high speed?high weft-insertion rates?high versatility and so on.As a key component of an air-jet loom,auxiliary nozzles charge with the significant task of the weft insertion,while the air consumption of the auxiliary nozzle accounted for about 75% of the whole air consumption during the weft insertion.The performance of the auxiliary nozzle has a direct influence on working efficiency and energy consumption of the air jet loom.Apart from manufacturing processes,the performance of the auxiliary nozzle is more dependent on its structural parameters,such as the nozzle diameter,the entrance diameter,the number of injection holes,distribution manner of injection holes,etc.Therefore,to improve the performance of the auxiliary nozzle,the study of the optimization of its structural parameters is very significant.A 3D model of the flow field of the auxiliary nozzle for weft insertion is established based on Solidworks,then the model is meshed with Hypermesh,and the boundary conditions of the gilded model are setted up with gambit,the numerical simulation on the flow field of the auxiliary nozzle for weft insertion can be accomplished by the CFD software Fluent.Thereafter,the comprehensive comparison of injection characteristics and air consumption are carried out by simulating the geometrical models of Auxiliary nozzle with different structure parameters under the condition of same gas pressure and injector orifice area,and the evaluation method is proposed to estimate the comprehensive performance of the different type of the auxiliary nozzle.Based on the above simulation analysis,some useful results are obtained: 1)With the increase of the distance from nozzle exit,the airflow velocity reaches the maximum at the nozzle exit and then the airflow velocity on the central line of the auxiliary nozzle decreases gradually.2)The performance of the auxiliary nozzle with the distribution of center of the circular is better than that of annular distribution.3)With the decrease of the center hole diameter of auxiliary nozzle,the airflow velocity of auxiliary nozzle with a central annular distribution of the same size but different diameter decreases.4)Under the condition of same orifice area,air consumption of the auxiliary nozzle decreases gradually with the number of injector orifice,and the air consumption of the style of 8K04 of the auxiliary nozzle is minim.5)It is found that the comprehensive performance of the style of 7K04 of the auxiliary nozzle with high airflow velocity and low air consumption is the best according to the results of the numerical simulation,so the style of 7K04 of the auxiliary nozzle is suitable for the majority of textile fabric weft insertion.and the tapered orifice auxiliary nozzle appeared some problems of large gas consumption,but its airflow velocity is the fastest of all,the tapered orifice is suitable for heavy fabric weft insertion.the comprehensive performance of the style of 5K03?6K05?8K04 of the auxiliary nozzle are better than the single circular orifice of the auxiliary nozzle.For further optimizing the structure of the auxiliary nozzle,using numerical simulation technology and considering air consumption and the maximum airflow velocity at the exit of the auxiliary nozzle for optimizing evaluation,using analysis of Multi-target Orthogonal Experiment,the influence of the nozzle diameter,the transition length,the entrance diameter and spraying angle of the auxiliary nozzle on air consumption and the maximum velocity at the exit of the auxiliary nozzle was discussed.An optimal combination of structural parameters is discovered by comprehensive Weighting method.The confirmation experimental results show that the nozzle diameter is 1.5mm,the transition length is 8mm,the entrance diameter is 3.2mm,spraying angle of the auxiliary nozzle is 5°,and air consumption and the maximum velocity at the exit of the auxiliary nozzle is the optimal.In order to fabricate the auxiliary nozzle by Selective Laser Sintering System,a researcher on the building quality of the SLS is conducted.Considering over-sintering depth,the sintering density,and dimension variation in Z direction for optimizing evaluation,using analysis of Multi-target Orthogonal Experiment,the influence of the laser power,scanning speed,preheating temperature and sintering thickness on Sintering quality was discussed.an optimum parameter combination of product quality is discovered by comprehensive Weighting method.The confirmation experimental results show that the laser power is 16 W,the scanning speed is 3m/s,the preheating temperature is 98?,the sintering thickness is 0.15 mm,and the quality of specimens is the optimal.On this basis,the auxiliary nozzles are Fabricate by SLS.Measurement and analysis of the auxiliary nozzles are carried out with the YF-1050 T optical image measuring instrument and the results show that the accuracy of the auxiliary nozzles made by SLS meets the requirements in size,so the auxiliary nozzles for the experiment can be made by Selective Laser Sintering System.The auxiliary nozzles made by SLS are tested on test platform of airflow rate from auxiliary nozzle,and The velocity distribution curves on the central line of the auxiliary nozzles are obtained.It is found that flow field simulation analysis is in accordance with experimental value.