Abstract

This article presents a mathematical model of liquid transport in twisted yarns, considering that yarn twist determines the pore configuration that ultimately decides the extent to which wicking takes place in a yarn. It is shown that that the equilibrium wicking height of liquid initially increases with the increase of packing density of yarn due to higher capillary pressure resulting from reduction of pore size. A further increase of packing density causes a reduction in equilibrium wicking height. The earlier theory of pore geometry in yarns has been modified by including fibre contacts in yarn cross-section for more realistic estimate of pore shape factor and pore size. Unlike previous studies, the present model is derived through a probabilistic arrangement of fibres in yarns and does not assume any theoretical arrangement. The model developed in this work is found to predict the complete experimental results quite satisfactorily for three structurally disparate variants of polyester filament yarns.

• Highlights

• Introducing probabilistic theory for fibre contacts into pore geometry to modify previous theories on pore characteristics

• Pore size and pore shape factor collectively influence the liquid column height, which varies with packing fraction (or twist)

• Modified theory of pore geometry predicts an inverted ‘U’ shape curve of wicking as per experimental evidences

摘要

本文介绍了加捻纱线中液体传输的数学模型，考虑到纱线捻度决定了孔隙配置，而孔隙配置最终决定了纱线中发生芯吸的程度。结果表明，由于孔径减小导致毛细管压力升高，液体的平衡芯吸高度最初随着纱线填充密度的增加而增加。填充密度的进一步增加导致平衡芯吸高度的降低。早期的纱线孔隙几何理论已通过在纱线横截面中包含纤维接触进行修改，以便更现实地估计孔隙形状因子和孔隙尺寸。与以前的研究不同，本模型是通过纱线中纤维的概率排列得出的，并不假设任何理论排列。

• 强调

• 将纤维接触的概率理论引入孔隙几何结构以修改先前关于孔隙特征的理论

• 孔径和孔形状因素共同影响液柱高度，液柱高度随填充率（或扭曲）而变化

• 根据实验证据，孔几何的修正理论预测芯吸的倒“U”形曲线