气流槽聚型集聚纺纱系统集聚过程及机理分析

为了探讨气流槽聚型集聚纺纱系统的集聚过程和机理,首先分析了集聚过程的气流流动状况,然后利用Matlab模拟了须条在集聚气流场中的运动轨迹,并分析了气流对须条的集聚效果.研究结果表明:须条进入凹槽入口前,只受气流集聚作用,当进入凹槽后,受到气流集聚及凹槽形状集聚共同作用;气流对须条边缘纤维具有集聚作用,吸气负压大小影响气流对须条边缘纤维的集聚宽度;不同厚度须条的纤维受气流作用位置发生变化,在须条截面内发生内外转移现象.     

气流槽聚型长纤维紧密集聚纺纱系统流场模拟与分析

采用SolidWorks软件建立气流槽聚型长纤维紧密集聚纺纱系统集聚区的流场计算模型,然后运用Gambit软件进行网格划分,最后应用Fluent软件对集聚区进行流场模拟和数值计算,得出流场的静压和速度分布规律.研究结果表明:纤维束的干扰或阻挡使凹槽内部的流场速度等高线和压强等高线被分割;x,y和z轴向速度的变化规律各异,且共同完成对纤维束的气流集聚作用;气流负压值不宜过大,避免纤维束被过早吸附造成缠绕影响集聚效果.     

气流槽聚型紧密纺纱系统集聚区长度设计

在研究气流槽聚型紧密纺纱系统前牵伸罗拉、前牵伸皮辊和槽型集聚罗拉对集聚区长度影响的同时,首次利用几何-概率方法表述握持须条钳口截面上一侧伸出的纤维丛长度分布,并通过实验分析得到集聚区长度的计算方法.结果表明:在气流槽聚型紧密纺纱系统中,集聚区长度受前牵伸罗拉半径的影响最大,其随着前牵伸罗拉半径的增大而增大.同时,为保证正常纺纱,避免须条在集聚区断裂造成断头,集聚区长度范围应为伸出钳口纤维累计概率为75%~100%时所对应的长度,纺棉时集聚区长度应该在20.8~38mm之间.     

气流槽聚型紧密集聚纺纱系统阻力传递机理探讨

为探讨气流槽聚型紧密集聚纺纱系统集聚区内纺纱张力引起的阻力传递机理,分析了集聚区内气流速度和动摩擦因数的变化规律,研究纺纱张力的传递过程.研究结果表明:在凹槽中,从纱线输出点到纤维束与凹槽的接触点,气流法向速度分量逐渐减小;间隔段包围弧对应的中心角决定了切向摩擦因数分量大小;纺纱张力的变化与动摩擦因数、导纱钩处张力、吸风孔间距及气流力密切相关.     

气流槽聚型紧密集聚纺力矩传递分析

为了探讨气流槽聚型紧密集聚纺纱系统集聚区内的力矩传递,首先分析了集聚区内纺纱张力矩和气流力矩的传递过程,然后分析了纱线自身回转产生的扭矩与纺纱张力矩和气流力矩的关系.研究结果表明:影响力矩传递的主要参数有纺纱张力、吸气负压值等;纺纱张力矩与气流力矩决定捻度是否会越过纤维束与凹槽底部的初始接触点上传至前钳口;适当提高吸气负压值可以缓解纺纱张力.     

网格圈型紧密赛络纺不同吸风槽集聚效果的模拟与分析

通过改变网格圈型紧密赛络纺吸风槽的结构,建立不同排列方式吸风槽的紧密赛络纺模型,采用Fluent流场模拟软件,分别对V型槽、直向平行槽、斜向平行槽模型进行集聚区域的气流运动模拟,根据模拟结果,分析纤维的集聚机理.研究结果表明,V型槽集聚效果最好,直向平行槽次之,斜向平行槽较差.设计并制作吸风槽不同排列方式的异形管,采用相同的工艺参数,在紧密赛络纺纱机上纺制相同原料的纱线,对所纺制的纱线进行性能对比试验,试验结果表明,用V型吸风槽纺制的纱线综合性能最优.     

Fluent在气流聚集型纺纱装置中的应用

利用fluent软件对气流聚集型纺纱装置中的气体流场进行建模、分网、加载,得到气流流经尘笼及抽气孔处的速度矢量和压力分布图.说明了纤维在气流场中的运动规律,为如何合理有效地利用气流技术加工出质量好、成本低的产品,以及利用气流技术发展新工艺、新方法提供了可靠的理论基础.数值模拟与试验结果对比表明:数值模拟结果与实际情况比较吻合.数值计算还可以进一步优化气流聚集型纺纱装置的结构参数,通过气流集聚,绝大多数纤维被纺入纱线内,使纱线强度、抗磨性及抗断裂性能增强,纱线表面更光滑,改善了纱线的品质.     

集聚纺集聚区气流流动规律及集聚效果的数值研究

为探讨网格圈式集聚纺集聚区气流流动规律及气流对须条的集聚效果,建立计算流体动力学(CFD)模型,对集聚纺集聚区的气流流动进行了三维数值研究,并根据计算结果就气流对须条进行集聚的机理、几个重要的结构参数及工艺参数(如吸风槽倾角、吸风槽形状、吸风槽宽度及集聚负压)对集聚效果的影响进行了分析.研究结果表明:集聚区的气流静压值低于外界的大气压力,集聚区外围越靠近吸风槽,压力越小,气流速度越高.由于内外压力差和速度差的存在,从前罗拉钳口输出的纤维须条向吸风槽汇聚,宽度逐渐变窄.吸风槽倾角为10°时有利于集聚效果的提高;弧线型和折线型吸风槽的集聚效果优于直线型吸风槽;集聚负压在一定范围内的变化对集聚效果的影响不明显;增大吸风槽宽度有利于气流对须条的集聚.     

集聚纺纱的发展现状及展望

针对传统环锭纺存在加捻三角区这一缺陷，详细介绍了用于消除加捻三角区以减少纱线毛羽的集聚纺的类型、特点以及集聚纱的优异品质，并展望了集聚纺的发展前景。就目前3种典型的集聚纺纱系统进行了对比分析，比较之下，C型集聚纺纱系统优于另外两种。与传统环锭纱相比，集聚纱在纱线结构、米绕、合股、上浆、织造、针织、经编、原料使用以及产兵价格等方面具有显著的优势。     

网格圈型紧密集聚纺不同吸风槽集聚效果的模拟与分析

为明确网格圈型紧密集聚纺不同吸风槽的集聚效果,采用SolidWorks软件建立集聚区三维模型,利用Fluent6.3软件模拟直型槽、斜型槽、异型槽3种槽型集聚区的气流速度分布.研究表明,异型槽的集聚效果最好,斜型槽最有利于须条的输出,且斜型槽有使须条产生翻滚扭转的可能性.     

Numerical Computation in Airflow Field of Compact Spinning with Pneumatic Groove

In compact spinning with pneumatic groove,the computational fluid dynamic model,computed with parallel technologies Fluent 6.3,is developed to simulate the flow field in condensing zone with 3D computational fluid dynamic (CFD) technology.Flowing state,distribution rules of static pressure,and velocity in condensing zone are characterized and analyzed.The results show that the fiber bundle in compact spinning with pneumatic groove is compacted by airflow and the shape of the pneumatic groove,and the static pressure in condensing zone is negative,as well as the velocity of airflow in condensing zone is not zero.The fluctuation frequencies of the static pressure and velocity near the bottom of the pneumatic groove are relatively higher,and the number of the fluctuation is equal to that of the round holes in condensing zone.     

Study on Airflow Field of Condensing Zone in Compact Spinning System with Perforated Drum

Negative pressure plays a very important role in compact spinning system. To know airflow field and its distribution is helpful to look into the condensing principle of fiber bundle. Therefore, computational fluid dynamics (CFD) software was used to simulate airflow field in this paper. Airflow velocity distributions both in different fiber layers and under different negative pressures were discussed. The results indicate that airflow velocity in upper layer of the fiber bundle is greater than that in lower layer.Airflow velocities in both X and Y axis directions have a positive correlation with negative pressure. It can provide a theoretical base to make high quality compact yarns in productive practice.     

Utilizations of Statistics on Optimizing Parameters in Compact Spinning with Pneumatic Groove

The compact spinning with pneumatic groove utilizes transverse air force and mechanical force of the pneumatic groove to condense fiber bundles to eliminate the spinning triangle.Range analysis and var...     

Comparison of Flow Field Distribution and Characteristic on Different Compact Spinning Systems

Numerical simulation models of compact spinning with perforated drum,punched apron and lattice apron were established and computerized with computational fluid dynamics (CFD)software.Characteristics of airflow in condensing zone were achieved.Velocity vectors of the flow on different systems were contrasted and discussed.Then,trajectories of fibers in condensing zone were simulated by a specially designed MATLAB program routine.The result of the simulation clarified the compact mechanism of the compact spinning systems.Also,it applied a guideline for reasonable utilization of the airflow in condensing zone.     

Motion Analysis of Fiber Band in Compact Field of Compact Spinning

The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting angle of suction slot in profile tube, additional twists created by fiber band＇s rotating around its own axis and ultimate twists in compact yarn are deduced accordingly. The existence of additional twists is also verified through experiments.