Numerical Simulation of Airflow Characteristics in Interlacers with Yarn Ducts of Various Cross-Sectional Shapes

摘要

The aims of the present work are to discuss effects of cross-sectional shapes of yarn duct on the performance of interlacers and to propose knowledge for designing better interlacers by numerical simulations of compressible airflow in the yarn duct of interlacer. We used a commercial CFD software package ANSYS CFX where a finite volume method with an upwind difference scheme is applied. Results obtained are as follows: (1) The yarn opening and tangling action is caused by high dynamic pressure at the yarn duct center. In addition, it is important to form an airflow pattern which makes a yarn frequently go and come between high speed airflow region (jet region) and low speed airflow region (eddy regions) in the middle section of yarn duct for the purpose of producing the interlaced yarn with large number of opening and tangling parts. (2) The yarn opening is done in the region where an air jet issuing from the air jet nozzle hits a yarn directly. In contrast, the path lines of airflow in the yarn duct are spiral and this spiral flow has an effect on the yarn ballooning. (3) The high supplied air pressure makes the dynamic pressure high at the yarn duct center. However, too high supplied air pressure makes the yarn stay at the yarn duct wall opposite to the air jet nozzle for a long time, thus the number of tangles is not increased.