Numerical investigation of spinneret geometric effect on spinning dynamics of dry‐jet wet‐spinning of cellulose/[BMIM]Cl solution

Abstract

In this study, the effect of spinneret geometry, including the entrance angle a of the entrance channel, the length L s , and the diameter D 0 of the exit channel, on the spinning dynamics of dry-jet wet-spinning of cellulose/1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solution was simulated by using finite element method. Based on the mathematical model of dry-jet wet-spinning established in our previous work (Xia et al., Cellulose 2015, 22, 1963 the radial and axial profiles of velocity, pressure, and shear rate in the spinneret and the profiles of diameter, temperature, and tensile stress in the air-gap region were obtained. From the simulated profiles, the effect of spinneret geometric parameters on the flow behavior and the pressure drop of polymer solution in the spinneret and the die-swell ratio near the spinneret was discussed. The entrance angle a of the entrance channel mainly influences the flow behavior of polymer solution in the spinneret and the die-swell effect near the spinneret. As the decrease of the entrance angle a of the entrance channel, the vortices in the spinneret could be removed and the die-swell ratio decreases. The increase of the length L s of the exit channel results in the increase of pressure drop in the spinneret and the decrease of the die-swell ratio. It is also found that the increase of the diameter D 0 of the exit channel reduces the flow velocity of polymer solution and decreases the pressure drop in the spinneret at a constant mass flow rate.

Nanopillar templating of biopolymer hydrogels augments stiffness and strength

“…Consequently, the converging brous network is more highly aligned within the P500 lm, leading to a denser network of rigid bonds, and the lm is unable to stretch as much as the P300 lm. The situation is analogous to ow convergence just before the entrance region in a spinneret 34 .…”

Production of hollow ceramic rods by SHS extrusion

“…Явление разбухания струи известно и достаточно хорошо изучено в теории и практике экструзии растворов или расплавов полимеров. Суть эффекта заключается в увеличении диаметра струи материала в 3-4 раза по отношению к диаметру выходного отверстия фильеры [5][6][7]. После выхода материала из фильеры образующийся стержень имеет внешний диаметр больший, чем диаметр отверстия фильеры.…”

Analytical modelling of dry-jet wet spinning

“…From the previous discussion, it is seen that a mathematical model for the spinning process is useful for understanding the relationship between the spinning conditions and fiber properties [17,18]. Recently Xia et al [2,4] suggested a full 3-D model to predict numerically the fiber diameter along the spinning line, and important information was revealed. The numerical results can be used for optimal design of the spinning process, however, numerical simulation can not pick out an explicit relationship among spinning conditions, spinneret structure, and fiber properties.…”

“…As shown in fig. 1 the dry-jet wet spinning process is described in [4]. The spinning solution enters the spinneret.…”

“…Wet spinning is a widely used technology in polymer science and textile engineering [1][2][3][4][5][6][7]. Dry-jet wet spinning technology, a modification of wet spinning, combines both the advantages of melt spinning and wet spinning, which can be used to fabricate high-performance fibers [8][9][10][11][12].…”