多圆孔辅助喷嘴喷孔结构参数灵敏度分析

Sensitivity analysis of orifice structure parameters of multi-roundhole auxiliary nozzles

为探究多圆孔型结构喷孔对喷气织机辅助喷嘴喷射性能的影响规律,获得更好的喷嘴结构和引纬质量,文章以多圆孔辅助喷嘴为研究对象,进行多圆孔辅助喷嘴结构参数灵敏度分析。首先,采用拉丁超立方采样(LHS)抽取所需实验样本并建立各样本的流场模型,获得最大出口速度作为性能评定指标。其次,基于支持向量回归机(SVR)建立辅助喷嘴结构参数与最大出口速度间的数学代理模型。最后,采用Sobol全局灵敏度分析法求解结构参数的灵敏度,得到结构参数对其最大出口速度的一阶灵敏度系数和全局灵敏度系数。结果表明:喷孔直径和孔心距对最大出口速度的影响较大,喷孔位置和喷孔锥度的影响较小。

Air-jet loom uses compressed gas as the traction force of yarn,which has the characteristics of fast weft insertion speed and high efficiency,but its gas consumption is large,which is against the green manufacturing and carbon neutralization advocated in modern society.The reduction of energy consumption depends on the precise control of key parts’process parameters and scientific analysis methods.The auxiliary nozzle,a key component of the air jet loom,guides weft with the main nozzle.The structural parameters of auxiliary nozzles,the aperture of jet holes,the number of jet holes and so on directly affect the weft insertion quality of air jet loom.Most studies use the control variable method to investigate the influence of structural parameters on weft insertion effect.However,there are various errors inevitably in the process of machining,numerical simulation and test,which will affect the weft insertion effect of the auxiliary nozzle.The influence of the uncertainty of the structural parameters of the auxiliary nozzle on the uncertainty of its comprehensive performance is not clear.In order to obtain better structure and weft insertion effect of the auxiliary nozzle,the sensitivity of structural parameters of the multi-hole auxiliary nozzle was analyzed by taking the multi-hole auxiliary nozzle as the research object.Firstly,the maximum outlet velocity of 4-hole,5-hole and 6-hole auxiliary nozzles was studied by numerical simulation.On this basis,the nozzle aperture,nozzle taper,nozzle location and nozzle center distance of the auxiliary nozzle were selected as the research parameters,and the maximum outlet velocity was used as the performance evaluation index of the auxiliary nozzle.The value ranges of four structural parameters were determined,and 500 sets of data were extracted from the value ranges of the structural parameters using Latin hypercube sampling.The maximum outlet velocity corresponding to each group of parameter combinations was obtained by numerical simulation.Among them,450 groups of data were randomly selected for training model,and the remaining 50 groups of data were used for testing model.Finally,the relationship model between the structural parameters and the maximum outlet velocity was established by using the intelligent algorithm based on support vector regression machine,and the first-order and global sensitivity coefficients of each structural parameter were solved by using Sobol method.The results show that the maximum outlet velocity of the six-hole auxiliary nozzle is the largest,and the gas flow rate makes the auxiliary nozzle have better cluster performance,and its comprehensive performance is the best among the three kinds of auxiliary nozzles.The accuracy of the model based on support vector regression machine is very high,and the mean square error of the training set and test set are 0.032 and 0.016 respectively.The uncertainty of orifice diameter and orifice center distance brings the most uncertainty to the maximum outlet velocity,while the uncertainty of orifice location and orifice taper contributes little to the uncertainty of maximum outlet velocity.The first-order sensitivity coefficient of each parameter is very close to the global sensitivity coefficient,and the interaction between each parameter is not obvious.The contribution of the uncertainty of auxiliary nozzle structural parameters to the uncertainty of comprehensive performance evaluation index can provide reference for the structural design and optimization of auxiliary nozzle.When designing the auxiliary nozzle structure,the hole diameter and hole center distance are of higher priority than the position and taper of the hole,so as to minimize the uncertainty of the hole diameter and hole center distance.The filling insertion process of air jet loom is very complicated.The research of auxiliary nozzle should adopt more intelligent algorithm to study more structural parameters and explore the influence of parameters and their interaction on filling insertion quality,so as to provide guidance for reducing the energy consumption of air jet loom.