Finite Element Analysis Of Yarn Hairiness Deduction Mechanism

If yarn hairiness is too much, it not only affects the following process, but also affects the quality of product. Yarn hairiness generally arises in spinning process and increases in winding process. With the enhancing of winding machine speed, how to control the hairiness increasing extent on the high speed winding machine becomes a problem. Developments in science and technology have made airflow, especially high speed airflow, widely used in textile production.Researchers around the world use the high speed airflow in air-jet to reduce yarn hairiness by installing an air-jet on spinning machine or winding machine. In the anterior research, a reducing hairiness jet is designed and installed on winding machine; it is proved by experiment that yarn hairiness increasing extent is reduced. But the research was mostly based on experiment, and the movement state of high speed airflow in the reducing hairiness jet is not full analyzed, so the hairiness-decreasing principle can't be explained.There are mainly three parts in this study: first, the digital simulation of the high speed airflow in the reducing nozzle; second, designing and installing of the simulated nozzle; and third, the study on the yarn's movement in the simulated nozzle.1. Based on reasonable simplification, the digital simulation of the high speed airflow in the three model of the reducing nozzle is done with the ANSYS CFD. The result shows that the airflow in the reducing hairiness jet is vortex.2.Magnifying dimension of the nozzle with five times according to the principle of Reynolds number similar to catch the yarn's movement in the nozzle, the simulated nozzle which made of organic glass was installed on the 1332 winding machine.3. Use KONDAK high speed photography to catch the yarn's movement in the reducing hairiness jet in different yarn path diameter and air press. The yarn moves as the shape of column-helical in the reducing hairiness jet, that is to say, under the effect of airflow, the yarn forms air loops, going upwards while rotating in column-helical way, which is in line with the theory analysis.On the whole, it seems that the reduction of yarn hairiness mostly attributes to the function of vortex when the yarn gets through the reducing hairiness jet. Vortex makes the yarn to form air loops, moving in column-helical way. In this process, yarn hairiness is wrapped into yarn body so that yarn hairiness decreases.