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.

Additional Twists of Yarn Produced by System of Compact Spinning with Lattice Apron

Based on the flow simulation in the condensing zone of compact spinning with lattice apron and a bead-elastic rod dynamic model of the flexible fiber,trajectories of fibers with different negative pressure are simulated by specially designed Matlab procedure.Then displacement components of fibers at YZ profile under different negative pressure conditions are extracted and compared.The results show that the fibers of different initial positions gradually converge,and are interlaced for position change in yarn cross-section,caused by the airflow in the condensing zone.Finally,compact-spun yarn with different negative pressure and conventional ring spun yarn are produced and their twists are tested.Both the results of simulation and experiments illustrate the existence of additional twists.Also the relationship between additional twists and negative pressure is verified.

Simulation and Analysis of Fiber Motion in Condensing Zone of Compact Spinning with Lattice Apron

To get fiber motion in condensing zone of compact spinning,velocity of this area is achieved by simulation,and then a bead-elastic rod fiber model is established.Based on simulation and dynamic analysis on this zone,governing equations are constructed and Runge-Kutta approach is used.Lastly,trajectories of fibers are calculated by specially designed Matlab procedure according to the principles mentioned above.Results show that fiber motions at different initial positions are different;X-axis velocity component makes fibers gathering on sides of suction slot;Y-axis airflow gets fibers gradually close and then stick to the surface of lattice apron.Fiber motions also reflect that the compact spinning process in condensing zone can be divided into three parts:fast convergence zone,adjustment convergence zone,and steady convergence 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.

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.

Modeling Additional Twists of Yarn Spun by Lateral Compact Spinning with Pneumatic Groove

Compact spinning with pneumatic grooves is a spinning process to gather fibers by blended actions of airflow and mechanical forces.Modified from the ring spinning system,the lateral compact spinning with pneumatic grooves can improve yarn appearance and properties due to generated additional twists.In this study,we investigated additional twists of the lateral compact spinning with pneumatic grooves via a finite element(FE)method.An elastic thin rod was used to model a fiber to simulate its dynamic deformation in the three-dimensional space,and the space bar unit was used to simplify the fiber model for the dynamic analysis.The stiffness equation of the elastic rod element and the dynamic equation of the rigid body mass element were derived from the differential equation of the elastic thin rod.In the analysis of the nonlinear geometric displacement of the space elastic thin rod unit,the large deformation problem was solved with the stepwise loading successive approximation.The simulation results explained the mechanism of generating additional twists,and the experiment results proved the existence of additional twists.The study demonstrated that the FE model is effective for predicting additional twists of fiber bundles in the agglomeration zone,and for simulating the fiber motion in the compact spinning with pneumatic grooves.

Modeling and analysis of the compact spinning yam structure by interference

The fiber stress and elongation after the yam twisting has been analyzed in this paper. A method has been proposed to improve the strength of compact spinning yam. A structure model of the interference compact spinning yarn was established. It theoretically proves that interference compact spinning yarn has higher strength than that of traditional compact spinning yarn.

Twist Distribution of Fiber Bundle in Compact Zone of Compact Spinning with Lattice Apron

In the compact spinning with lattice apron, twist distribution of the fiber bundle in the compact zone is influenced by the airflow. In order to study the twist change of the fiber bundle in the compact zone,a theoretical model was established and the twist was calculated based on the experimental parameters. Experiments were carried out to verify the theoretical model. Theoretical and experimental results show consistency. The study indicates that the twist distribution of the fiber bundle in the compact zone is related to the tension, the offset angle and the linear density of the fiber bundle.

Numerical Study on Effect of Suction Slot Geometric Parameters on Airflow Field in Compact Spinning

The airflow field in the condensing zone is crucial as it affects the fiber condensing,additional twists,and consequently yarn properties.Parameters of spinning and suction slot geometric were found to be key factors influencing the airflow characteristics.To develop a better understanding of the complex airflow field within the pneumatic compact spinning system with lattice apron,a 3D numerical simulation model was built and the influence of negative pressure and geometric of suction slot was investigated.The results reveal that the accelerating air from the top of the suction slot generates transverse condensing force and downward pressure on the fiber strand.The inclination angle has a small effect on airflow velocity.The absolute z-velocity and c-velocity in the positive a-axis were both increased with increasing the slot width from 1.0mm to 1.5 mm.An arc suction slot increased the absolute z-velocity and a-velocity compared with a linear one,thus benefiting fiber condensing.By decreasing the outlet negative pressure to-3kPa,the airflow velocity increased significantly.

Condensing Effect of Suction Slot in Compact-Siro Spinning on Fiber Strands

Compact-siro spinning is a new kind of spinning technique which combines compact spinning and siro spinning,and widely put into practice. Based on the airflow data in the condensing zone,it builds the geometrical model of fiber strands,and then the trajectory of single fiber can be got. The difference of trajectory and compact effect of fibers strands is also analyzed in the condensing zone of three different suction slots. By comparing with the data of three different suction slots,it selects the compact-siro spinning suction device whose yarn has the best overall performance. The theory analysis gives foundation and explanation for experiment,and also provides theoretical basis for optimizing the properties of compactsiro yarn in production practice.

空位缺陷硅烯纳米带结构与自旋极化电子性质的密度泛函紧束缚研究

随着纳米电子器件和自旋电子学的不断发展,对小尺寸的纳米硅材料物理和化学性质的研究是研发新型微电子材料器件的基础.硅烯纳米带在实验制备和理论研究中均备受关注.本研究利用基于自洽电荷的密度泛函理论紧束缚方法,研究了不同宽度的硅烯纳米带的结构、稳定性和自旋极化电子性质.研究发现,稳定的完美和带有空位缺陷的硅烯纳米带表现为带有曲翘褶皱的蜂窝结构.纳米带边缘的曲翘度大于中心位置.空位缺陷更容易出现在纳米带边缘.纳米带的宽度可实现完美的硅烯纳米带的半导体性质和金属性之间的转换.硅烯纳米带中出现空位缺陷可有效调控纳米带自旋电子性质从半导体向金属性转变、半导体向半金属性转变,及金属性向为半导体或者半金属性质的转变.这种自旋电子性质的调控手段使得该种纳米材料在纳米电子自旋器件上有着潜在的应用价值.

An Overview on the Spinning Triangle Based Modifications of Ring Frame to Reduce the Staple Yarn Hairiness

Traditional ring spinning system is associated with the several limitations, one of which is yarn hairiness. The awareness has been vibrantly growing among the spinning mills for reducing staple yarn hairiness because of its detrimental effects on the subsequent processes (i.e., weaving, knitting, dyeing etc.) and the quality of resultant textile products. As a result, modified form of ring frame has attracted a lot of attention among the researchers for making yarn with the lower level of hairiness value. Besides the raw material parameters and some processing variables, spinning triangle (ST) is the most critical region that has decisive influence on the distribution of fiber tensions and their spatial orientations and shapes in staple yarn body. Thus, using appropriate methods to control the spinning triangle geometry actively has been a vital issue in the field of yarn hairiness reduction. In this paper, it is attempted to make an overview on the spinning triangle based modifications of ring frame that have been designed and destined to reduce hairiness. However, agent aided ring spinning system has also been briefly discussed in this paper as well.

青泽CompACT^3紧密纺技术

紧密纺越来越多地应用于中高支纯棉精梳纱领域,紧密纺技术与高品质纱线具有相同的含义。与传统环锭纺技术相比,紧密纺技术使得纱线质量在其他应用领域有了实质性的进步。该进步主要体现为纤维利用率的提高以及棉纺厂本身产量的提高。通过紧密纺技术使得纱线在后道加工过程中毛羽明显减少。

451 CompACT^3毛纺紧密纺细纱机

山东南山纺织服饰有限公司成功地使用451 CompACT3毛纺紧密纺细纱机,从纤维制品到服饰成品,所有的生产步骤均采用市场领先地位的机械制造商的机器设备和技术。介绍了紧密纺系统的功能和信息。

细号纱超轻薄服装面料开发实践

为提高纯棉服装面料质量,拓展产品功能的多样性,以长绒棉为原料,采用单纱和股线均为Z捻的同捻向新工艺,开发CJ 5.83×2×CJ 5.83×2 248×248 165.1 ZZ强捻细号纱超轻薄服装面料;通过介绍其工艺流程,分析各工序工艺参数及技术要点,以及测试集聚纺CJ5.83 tex经纬筒纱成纱质量及相关织物质量指标。指出:生产特细号纱的关键是做好原棉选择、前纺各工序工艺参数设置及车间温湿度控制;提高精梳落棉率、减小并条工序牵伸倍数、采取集聚纺纱等措施,能有效降低条干不匀率、提高纤维利用率和伸直平行度,可使单纱强度提高10%;采用集聚纺CJ5.83 tex合股强捻纱生产的超轻薄面料,透气性、吸湿性、耐磨性、防水性好,织机效率可达90%,坯布下机一等品率达92.4%。

集聚赛络纺纱导流装置的设计与应用

针对集聚赛络纺纱系统能耗较大的问题,设计3种导流装置,以降低集聚赛络纺纱系统的负压,达到节能降耗的效果。首先通过solidworks软件建立集聚赛络纺纱集聚区三维物理模型,利用fluent进行数值模拟,分析集聚区气流场的分布情况;然后通过纺纱实验进一步验证导流装置能够起到节能降耗的效果。结果表明:出口负压越大,集聚槽附近的速度越大,集聚槽上方的气流对须条起到挤压作用,使须条紧紧贴在网格圈表面,集聚槽侧向气流使须条宽度减小,须条表面的毛羽能够卷入到纱体表面,形成紧密的结构,从而能够减小甚至消除加捻三角区;使用所设计的3种导流装置(集聚负压1000 Pa)纺制出来的纱线与普通集聚赛络纱(集聚负压2000 Pa)质量相当,甚至更好。

环锭纺纱新技术的成纱机理及其应用

对比目前相对成熟且有代表性的环锭纺纱新方法,包括集聚纺、赛络纺、扭妥纺、柔洁纺的成纱原理、结构性能及优缺点等,发现每种新技术作用方式不同,其结构性能也各有区别,并以不同特征与风格适应不同类型的市场。

优选器材专件,提升再生涤纶纤维纱线质量

为了提升再生涤纶纤维纱线品质,以赛络集聚纺再生涤纶纤维14.76 tex针织纱为例,介绍再生涤纶纤维原料物理指标及性能;阐述再生涤纶纤维纺纱生产工艺流程及各工序工艺措施;重点对梳棉工序锡林针布用齿条、回转盖板用弹性针布、道夫针布齿条,细纱工序用钢领、钢丝圈、胶辊、胶圈、网格圈等器材专件及其工艺参数进行优选,分析器材专件对质量提升的作用;通过纺纱实例,对比优选器材专件前后赛络集聚纺再生涤纶纤维14.76 tex针织纱的质量指标。指出:为减少纤维损伤,在开清棉及梳棉工序采用柔性梳理工艺,以轻度开松、多梳少打、轻定量、低车速为原则,保证管道气流畅通;梳棉机宜选用柔性梳理用针布齿条或弹性针布、实现柔和梳理;胶辊、胶圈以不缠不绕为前提,钢领、钢丝圈、网格圈以实现纤维完好集聚、减少毛羽和棉结等为重点。

细纱机短车集聚纺负压系统应用分析

为了提高纱线质量、实现节能降耗,介绍短车集聚纺负压系统的技术要求及主要组成;根据负压主风管结构将集聚纺负压系统分为八边形大风管型、八边形小风管型、上置八边形风管型、上置双列圆风管型,从节电性能、负压平衡度、性价比及对粗纱架排列要求等方面,详细分析不同类型集聚纺负压主风管的优缺点,并阐述各型集聚纺负压系统的发展应用。指出:上置双列圆风管型集聚纺负压系统节电性能优,支风管车头车尾压差小、负压平衡度好,主风管制造成本低,安装工作量小,使用效果良好。