Abstract
The present study is concerned with numerical simulation of air flow in a yarn duct of an interlacer, which is an apparatus for yarn intermingling. A nozzle of circular pipe of inner diameter d(<D) is mounted perpendicularly to the yarn duct of circular pipe of inner diameter D and length L. The air is injected from the nozzle into the yarn duct. This complex incompressible air flow of the interlacer system is analyzed by a numerical calculation program, FIDAP, using the high Reynolds number k-ε model. The air flow in the yarn duct can be simulated well by this analysis for d/D≤0.5. For d/D≤0.75, however, the predicted results for air flow in the yarn duct are not in satisfactory agreement with the measurements. The effect of the value of d/D on the air flow in the yarn duct is discussed. It is clearly found that for d/D≤0.5 the circumferential air flow along the inner wall of the yarn duct is dominant, while for d/D≥0.75 the axial air flow is dominant. The interlacer with 0.5≥d/D≤0.7 is usually used in the practical interlacing processing, where the condition of the air flow largely changes from circumferential to axial flow. Furthermore,the ratio d/D has no great effect on the flow in the yarn duct for d/D≥7.
