Modelling yarn balloon motion in ring spinning

Air-drag on a ballooning yarn and balloon shape affect the yarn tension and ends-down (yarn breakage), which in turn affects energy consumption and yarn productivity in ring spinning. In this article, a mathematical model of yarn ballooning motion in ring spinning is established. The model can be used to generate balloon shape and predict tension in the ballooning yarn under given spinning conditions. Yarn tension was measured using a computer data acquisition system and the balloon shapes were captured using a digital camera with video capability during the experiments using cotton and wool yarns at various balloon-heights and with varying yarn-length in the balloon. The air-drag coefficients on ballooning cotton and wool yarns in ring spinning were estimated by making a "best fit" between the theoretical and experimental turning points. The theoretical results were verified with experimental data. The effects of air-drag and balloon shape on yarn tension are discussed.