关键词: 熔喷纤维, 珠链模型, 拉格朗日方程, 非牛顿流体, 黏弹力, 纤维直径

Abstract:

For accurately predicting the final diameter of fiber and revealing the mechanism of fiber formation, four types of non-Newtonian fluid constitutive equations, PTT, UCM, Giesekus and Rouse-Zimm, were introduced on the basis of Lagrange method and bead-chain model. The stress and resulting diameter of fiber in the air jet were predicted, respectively. The results indicate that: the viscoelastic forces calculated by different non-Newtonian fluid constitutive equations are different, thus the predicted results are different. Final diameter of fiber is affected by the difference between internal and external stress and the position of freezing point. Larger difference between internal and external stress generates faster decay rate of diameter. Fiber would have enough space to be drawn if the freezing point of fiber appears far away from the orifice. The fiber calculated by UCM fluid constitutive equation is the thickest, while the fiber predicted by Giesekus equation is the finest. The predicted results from Giesekus fluid constitutive equation show good agreement with the experimental results.

Key words: melt-blowing fiber, bead-chain model, Lagrange equation, non-Newtonian fluid, viscoelastic stress, fiber diameter