Chenchen Han

Theoretical analysis on the yarn twist mechanism of self-twist jet vortex spinning

In this paper, the hollow spindle receives self-twist modifying treatment, which makes the surface friction coefficient of the hollow spindle increase. When the sliding friction torque is enough to overcome the torsional stiffness of the fiber, under the force of the high-speed airflow, the fiber scrolls on the surface of hollow spindle, resulting in fiber twist, which increases the cohesion between the fibers, improving yarn strength. Based on the flow field simulation of the self-twist jet vortex spinning, it establishes the mechanical system of the free-end self-twist motion of the fiber in the flow field, and analyzes the fracture mechanism of the self-twist jet vortex spinning yarn. It provides more comprehensive support for the design and processing of the key components of the self-twist jet vortex spinning system.

Comparative analysis of different jet vortex spinning hollow spindle groove structures on yarn mechanism and yarn properties

According to the self-twist jet vortex spinning process, the free fiber end lays flat and rolls rotationally on the surface of the stationary hollow spindle under the high-speed rotating airflow and the tangential friction torque, which results in the self-twist of the fiber. The self-twist will be wound into the yarn body and increases the friction and the cohesion between the fibers in the yarn, which will improve the strength of the yarn. Based on mechanical analysis and numerical simulation, this article obtains the motion trajectory of the free fiber end and designed six different hollow spindle groove micro-feature structures. Combined with experiments, this article analyzes comparatively the influence of different hollow spindle groove micro-feature structures on the free fiber end and the yarn performance, which lays the foundation for the research and the development of jet vortex spinning.

Numerical simulation of fiber strands on condensing effect of suction slot in compact spinning with lattice apron

Compact spinning technology is through the airflow force to get fiber strands to be compacted in the condensing zone. In this paper, it makes a deeper study on the morphological changes and movement process of fiber strands in the flow field of condensing zone. Based on the airflow data in the condensing zone, the geometrical model of single fiber is built, and then the trajectory of single fiber can be got. The difference of trajectory and compact effect of fiber strands is also analyzed in the condensing zone of straight, oblique and deformed suction slots.

Comparative analysis on yarn mechanism and yarn properties of different jet vortex spinning systems

Changing the process of jet vortex spun yarn will result in the change of its structure, and further changing its properties. In this article a comparative study is carried out about three aspects, namely the internal structure of the nozzle, the internal flow field distribution of the nozzle, and the yarn properties of MVS861 and MVS870. The correlation between the yarn formation process and yarn properties will be discussed theoretically, which will be validated by designed experiments. There is significant meaning for researching the correlation between yarn formation process and yarn structure because, on the one hand, it can optimize the process of yarn formation and improve the structure of key components used to form yarn, and on the other hand, it can guide theoretically the design of the yarn structure.

Numerical simulation and analysis of airflow in the condensing zone of compact-siro spinning

Compact-siro spinning is a new kind of spinning technique that combines compact spinning and siro spinning, and is widely put into practice. In this paper, a simulation and characterization of the flow field in the condensing zone are made by computational fluid dynamics software. It mainly includes the distribution rules of static pressure and velocity. According to the relative references and factory condition, several orthogonal and control experiments have been done. Through testing the strength, evenness and hairiness properties and analyzing and comparing the results with the data of three different suction slots, we select the compact-siro spinning suction device whose yarn has the best overall performance. The theory analysis gives foundation and explanation for the experiment, and also provides a theoretical basis for optimizing the properties of compact-siro yarn in production practice.

Comparative analysis of traditional jet vortex spinning and self-twist jet vortex spinning on yarn mechanism and yarn properties

Because of the friction between the hollow spindle surface and the fiber end increasing, the fiber end rolls on the hollow spindle surface under the high-speed rotating airflow during the twisting process. The fiber gets self-twist, which will be wound into the yarn body. The self-twist of the fiber will increase the friction and the cohesion between the fibers in the yarn, which will improve the strength of the yarn. This article analyzes traditional jet vortex spinning and self-twist jet vortex spinning comparatively from the three aspects of the hollow spindle structure, the airflow distribution inside the nozzle, and the yarn performance. It is beneficial for exploring the yarn mechanism, the yarn performance, and the development of self-twist jet vortex spinning.