TWIST DISTRIBUTIONS IN THE FIELD OF LIQUID FRICTION

The twist distributions along a yarn depends on the properties of the yarn and on the mechanism of yarn-twisting (false twister, open end spinning and ring spinning frame).In this study, the twist distributions of yarn prepared under the various friction conditions are experimentally investigated, and numerically discussed for the yarn twisted in the high viscous fluid. The following results are obtained:1) It was recognized that the twist of the rotating yarn in the fluid distributes along the yarn axis, which is due to the fluid friction.2) When the twist distribution of the rotating yarn in the fluid is measured under constant tension, the moment of fluid friction MY is described by the following equation, in which the flow of the fluid is treated as Couette flow. hY: yarn length in the fluid (cm) η: viscosity (dyne•sec/cm2) Ω: angular velocity (rad/sec) RY: radius of the yarn (cm) RP: radius of the pipe (cm)3) The rigidity of the yarn under constant tension is measured by using the apparatus showing in fig. 3.4) The rigidity of the yarn depends on twist and tension.