圆盘式旋流纺的加捻气压对成纱的影响

为了掌握圆盘式旋流纺纱设备的加捻气压对成纱质量的影响,在圆盘式旋流纺纱机的其它工艺参数固定的条件下,分别改变旋流加捻器两级喷嘴的气压,纺制了20种长丝包芯纱,测试了所纺纱线的包缠牢度、断裂强力和断裂伸长等指标,并对测试结果进行分析。结果显示,圆盘式旋流纺纱加捻器的两级喷嘴气压的配置对成纱质量有较大影响。当第一喷嘴气压为0.30～0.35MPa,第二喷嘴气压为0.60～0.62MPa时,所纺纱线可以取得较好的包覆性能和强伸性能。     

喷气涡流纺工艺及其产品开发

研究喷气涡流纺中喷嘴气压、喷嘴入口与前罗拉钳口间距离对涤/棉70/30混纺纱、粘胶纱和竹浆纱纱线性能的影响,并对喷气涡流纱与环锭纱的成纱纱线性能进行了对比.研究表明:喷嘴气压与纤维刚度有较大关系,纤维刚度大,则喷嘴气压应高,以保证加捻的效率和成纱强力,一般应为0.40～0.55MPa;前罗拉钳口与喷嘴入口的距离与所加工的纤维长度有关,纤维长度大,则该距离应大,一般在13～16mm;喷气涡流纱的条干均匀度较喷气纱和环锭纱要差一些,但毛羽较之有显著减少.     

旋流纺闭合式纤维集聚机构的改进及成纱性能

 为了探究旋流纺新的引纱方法,本文在旋流纺闭合式集聚装置上作了改进,将其设计成附有引纱通道和引纱罗拉的集聚装置。成纱利用引纱方法将汇聚好的纤维束引出来,再利用旋流喷嘴加捻成纱。首先分析改进前后集聚装置的区别和成纱原理,然后通过改变旋流喷嘴的气压配置,对所纺纱线的断裂强力及毛羽两项纱线质量的主要性能指标进行了测试,分析喷嘴气压配置与成纱质量之间关系,并通过扫描电镜来分析纱线结构的变化。发现：这种成纱方法可以纺制出普通纯棉纱线,加捻气压仍然对纱线质量影响较大,纱线的外观和改进前的纱线不同。本结果为研究旋流纺新型汇聚装置提供参考。     

喷气涡流纺成纱工艺对色纺竹浆纤维针织物性能的影响

为研究喷气涡流色纺成纱工艺参数对色纺竹浆纤维针织物性能的影响,基于Box-Behnken设计方法,借助Minitab16软件,分析探讨了喷气涡流纺成纱工艺（喷嘴气压、纱线线密度、纺纱速度）对色纺竹浆纤维针织物断裂强力、透气性、悬垂性及耐磨性的影响。结果表明：纱线线密度减小,织物断裂强力下降,透气性和悬垂性先显著增加,而后略有下降;纺纱速度提高,织物断裂强力缓慢减小,透气性降低,悬垂性增加;喷嘴气压对针织物断裂强力、透气性、耐磨性均无显著影响,但当喷嘴气压增加时,织物悬垂性能先增加后降低;织物耐磨性主要受纺纱速度和纱线线密度的影响,且影响较为复杂。     

不同纺纱参数对双喷嘴假捻纱成纱结构的影响

比较和分析了双喷嘴喷气纱和涡流纱的差异。纱线强度主要是包缠纤维比例的函数。试验证明纤维在第二喷嘴成纱。第二喷嘴形成的捻度向后传递到牵伸系统,并抵消了第一喷嘴造成的反向捻度。通过调整入口的几何位置、喷嘴压力和纤维喂入的设计参数,可以对加捻三角区产生积极的影响,并可达到提高输出速度的效果。通过这些方法可略微改善成纱结构及性能。     

基于VIKOR法的喷气涡流纺纱工艺参数优化

设计了4因素4水平喷气涡流纺纱正交试验,并运用VIKOR法对试验工艺参数(喷嘴压力、前罗拉至纺锭的距离、纱线速度和预拉伸倍数)进行优化,优化目标为成纱的断裂强力、纱线条干CV值、细节、棉结和粗节。结果表明,喷嘴压力为0.4 MPa,前罗拉至纺锭的距离为20 mm,纺纱速度为340m/min,预牵伸倍数为2.2时,成纱效果较好。     

第一喷嘴结构参数对喷气纱强力的影响

喷气纺纱机上第一喷嘴的结构参数主要包括喷射孔角度、喷射孔直径和喷射孔数目,为说明各主要结构参数对喷气纱强力的影响,通过试验和回归分析的方法探讨了第一喷嘴各结构参数对喷气纱强力的影响。最终得到的结论是第一喷嘴的结构参数对喷气纱强力有较大影响,当喷射孔角度为42.9°,喷射孔直径为0.4 mm,喷射孔数目为4个时,成纱强力最高。     

利用涡流喷嘴改善环锭纱质量的工艺参数优化

在传统的环锭纺纱机上加装涡流喷嘴,可以有效地改善纱线表面的3 mm及以上长度的毛羽。通过3因素5水平正交实验,研究了涡流喷嘴气压、涡流喷嘴安装位置、所加工纱线的捻系数和细度对成纱毛羽性能、强度和条干不匀率的影响,得出纺纱线质量最好的最优工艺参数组合为:气压0.25 MPa,涡流喷嘴到前钳口的距离6.5 cm,捻系数400,细度18.2 tex。     

气道位置对旋流器减少细纱毛羽效果的影响

为了进一步优化旋流器的内部结构,更好地改善成纱质量,本文在前期研究基础上设计了三种不同气道位置的旋流器,并且在加工气压分别为0-0.25MPa下加工纱线。通过测定纱线的毛羽指数,并和普通环锭纺纱线进行对比,得出：当气道直径d=1.4mm,气道在纱道上的分布位置为1:2,加工气压为0.2MPa时,所纺纱线的毛羽指数达到最低。同时,利用流体力学计算软件ANSYS CFX对喷嘴内的气流场进行数值模拟和分析,研究了气流场对纱线毛羽减少的影响机理,并进一步阐明了气道位置和加工气压对喷嘴内气流场的影响。     

平行股线纺纱气压的组合优选

 采用正交试验的极差分析法和方差分析法,找出S向喷嘴气压、对冲喷嘴气压、Z向喷嘴气压中影响平行股线毛羽纠缠包缠效果的重要因素和一般因素,判断各个喷嘴气压对纱线质量是否存在显著性影响,从而找出最优气压组合,使所纺制的平行股线质量最佳。结果表明：对冲喷嘴气压是影响毛羽纠缠包缠效果的重要因素,它对纱线质量存在极显著的影响;S向喷嘴气压和Z向喷嘴气压是影响纱线质量的一般因素,对纱线质量影响不显著。且当S向喷嘴气压为0.1MPa、对冲喷嘴气压为0.2MPa、Z向喷嘴气压为0.1MPa时,所纺制的平行股线毛羽指数最小,即单纱间毛羽纠缠包缠的最好,单纱位置固定性最好。     

Study on a reducing-hairiness nozzle attached on the winding machine

A special hairiness-reducing nozzle was attached on a winding machine. The design and attachment of the nozzle should not change the yarn twist and strength. The hairiness-reducing mechanism of the nozzle was analysed, which utilised an air-jet to produce the rotating air stream to perform false twisting, detwisting and wrapping of the yarn so as to wrap the hairiness onto or twist it into the main yarn body, thus reducing the yarn hairiness. The position and method for attaching the nozzle were introduced. The hairiness index, hairiness appearance, twist and strength of the yarn, which was produced by the winding machine attached with the nozzle were examined. The results indicated that the processed yarns have their hairiness index lowered, hairiness appearance improved, and the twist and strength remained unchanged, which verified the hairiness-reducing effect of the nozzle. Fabric pilling property and surface features were measured for fabrics in which the filling yarns were through the winding machine with the nozzle. The results showed that the fabrics had less pilling and a smoother surface.     

The effect of air-jet nozzle structural parameters on new cotton rotor-jet spun yarn properties

In this paper, a hybrid spinning system the so-called “rotor-jet spinning method” which utilizes the air-jet nozzle in rotor spinning process is presented. Thus, air-jet nozzles with different structures of 90S, 90Z, 60Z, and 30Z (the values of 90, 60, and 30 are orifice angles and S and Z are air rotational directions) were designed and constructed and then mounted between the take-up nozzle position and doffing tube in a rotor spinning machine. The air-jet pressure was changed at 0.2, 0.5, 0.8, 1, 1.2 and 1.5 bar values. The physical properties of cotton rotor-jet spun yarns with yarn count 20 Tex and nominal yarn twist of 938 TPM were investigated and compared with that of normal rotor-spun yarn. The experimental results indicated that by utilizing a 90Z air-jet nozzle at 1 bar air pressure, the highest yarn tensile strength, abrasion resistance, and twist, and lowest elongation are obtained compared with those of normal rotor as well as rotor-jet spun yarns with 30Z, 60Z, and 90S air-jet nozzle types. However, the rotor-jet spun yarn irregularity produced with 90Z air-jet nozzle is almost identical to normal rotor-spun yarn. It is also shown that the rotor-jet spun yarn hairiness properties which were produced with a 90Z air-jet nozzle at air pressure values of 0.2, 0.5 and 1 bar is almost similar to normal rotor-spun yarn while the lowest yarn hairiness is achieved at air pressure value of 0.8 bar. The experimental results of this paper suggest that the newly developed rotor-jet spun yarn is superior to normal rotor-spun yarn from the point of view of yarn tensile, abrasion resistance, twist, and partially hairiness properties.

     

Numerical simulation of the yarn formation process in Rieter air jet spinning

This paper presents a three-dimensional numerical simulation of the airflow field inside Rieter air jet spinning nozzle. The velocity and pressure distribution were analyzed to describe the principle of yarn formation. The analysis of velocity components and static pressure revealed how the air vortices are created inside the nozzle. A theoretical study along with experimental verification was performed to investigate the influence of nozzle pressure on air jet yarn tenacity and the results were in good agreement. The results show that increasing nozzle pressure resulted initially in improving yarn tenacity but at high pressure tenacity deteriorates.     

喷气涡流纺涤纶纱工艺研究

研究了喷气涡流纺工艺对涤纶纱成纱性能的影响,改变涤纶纺纱工艺参数进行单因子实验.并通过正交试验得出喷气涡流纺涤纶纱的最佳工艺参数:导纱针到空心管的距离为0.5 mm,喷嘴气压0.6 MPa,纺纱速度为170 m/min.     

喷气涡流纺纱线细节产生机制分析

通过数值计算对喷气涡流纺喷嘴内部流场衰减规律进行探讨。讨论加捻腔中纤维的受力情况及涡流作用下的运动状况;建立倒伏在空心锭上的纤维自由端绕空心锭旋转的临界角速度与进入纱尾的纤维头端长度、纤维半径等参数间的函数关系,以临界角速度作为衡量纤维头端是否被抽拔的依据,解释喷气涡流纺落纤、成纱细节产生的原因。临界角速度随进入纱尾纤维头端长度的增加而增大;纤维半径越大,临界角速度越小,在同一喷嘴气压下,半径大的纤维纺纱时落纤、成纱细节较多;增加喷嘴气压对成纱强力有利,超过某临界值落纤、成纱细节增加,对成纱质量不利;增加喷嘴内部负压,适当减小前罗拉与空心锭的距离可减少落纤、细节的产生。     

喷气涡流纺成纱工艺对竹浆纤维色纺纱性能的影响

为进一步拓展喷气涡流纺织品种及提高传统色纺纱加工效率,利用Box-Behnken设计实验方案,借助软件Minitab 16,分析喷气涡流纺工艺参数对竹浆纤维色纺纱性能的影响。结果表明：成纱工艺对色纺纱断裂强度的影响较为复杂,其中纺纱速度及纱线线密度对色纺纱断裂强度的影响受喷嘴气压不同取值影响;色纺纱条干不匀主要受纺纱速度和纱线密度影响,提高纺纱速度使纱线条干不匀先减后增,而减小纱线线密度将显著恶化色纺纱条干;色纺纱毛羽主要受喷嘴气压和纺纱速度影响,降低喷嘴气压及提高纺纱速度均会使纱线毛羽增加;色纺纱直径主要受喷嘴气压和纺纱线密度影响,增加喷嘴气压或减小纱线线密度,均会使色纺纱直径明显减小。     

环锭旋流喷嘴纺麻混纺纱的性能

为改善麻纤维因自身性能缺陷与传统纺织工艺局限性所导致的成纱毛羽问题,将旋流喷嘴纺纱技术应用于精细化亚麻/长绒棉/天丝和大麻/棉/粘胶2种混纺纱的纺制,选择适当的细纱工艺参数并测试成纱后的主要性能指标。结果表明:当旋流喷嘴中通入的气流压强为0.1 MPa时,亚麻混纺纱的有害毛羽数量相对于传统环锭细纱降低了89.9%,压强为0.05 MPa时,大麻混纺纱的有害毛羽数量降低了99%;显微镜下2种混纺纱线的纱体结构紧密,纤维排列整齐,纱线表面光洁,大麻混纺纱中的黑色粘胶长丝均匀包裹在纱体表面,使得纱线色泽更为均匀;纱线断裂强力与条干不匀率稍有降低,但变化不明显。     

解析法评价旋转气流对喷气涡流纱的加捻强度

在对喷嘴内部流场数值模拟的基础上通过解析法研究旋转气流对喷气涡流纱加捻的强度。研究结果表明:旋转气流对喷气涡流纱的加捻强度是喷孔数目、喷孔倾角、喷孔直径、喷嘴直径、空心锭外径、喷孔出口速度(即喷嘴气压)、空心锭入口与喷嘴入口间距、尾端自由端纤维倒伏空心锭上部的高度、纱线直径等的函数。喷孔出口速度增加,旋转气流加捻强度增强;加捻喷嘴直径减小,旋转气流加捻强度增大;空心锭入口与喷嘴入口间距增加,旋转气流加捻强度减小;空心锭外径增加,旋转气流加捻强度增加。数值计算结果表明解析模型的有效性。     

Investigation of fiber migration in rotor-jet spun yarn

The fiber migration in the newly developed rotor-jet spun yarn is investigated utilizing the tracer fiber technique and a proposed image analysis method. Effects of rotor-jet spinning parameters including three air-jet nozzle types of 90Z, 60Z, and 30Z (the values of 30, 60, and 90 are jet orifice angles and Z is air rotational direction identical to rotor rotational direction) at different air pressure values of 0.2, 0.5, 0.8, and 1 bar were considered. The results showed that increasing of air pressure causes the fiber to locate in the interior position of the yarn for 90Z nozzle, while for 30Z and 60Z nozzle types, the fiber is moved toward the exterior position of the yarn. Conversely, it was indicated that with increase of air pressure mean migration intensity and migration frequency increase for 90z nozzle, whereas decrease for 30Z and 60Z nozzle types. In general, the mean migration intensity and migration frequency magnitudes of rotor-jet spun yarn with 90z nozzle type are significantly higher than those of normal rotor yarn particularly at the higher air pressure. However, rotor-jet spun yarns with 30Z and 60Z nozzle types exhibited much lower mean migration intensity and migration frequency magnitudes than normal rotor yarn.