The fundamentals of air-jet texturing.

摘要

Air-jet texturing is a well-established filament yarn processing technology that has been around for more than half a century. There is much debate about various aspects of the process in the literature such as the mechanism of loop formation, role of water in air texturing and the influence of process variables on air textured yarn structure. An attempt has been made in the current research to understand the above variables and other aspects of the process.; While the present research tends to support some of the earlier findings, this dissertation also presents findings that are contradictory to those in the literature. These include the following.; For the yarns and the range of air pressure used in the study (100--180 PSI), there is no significant effect of increase in air pressure on final air textured yarn properties. This is confirmed by image analysis of air-textured yarns, the results of online tension measurements and tensile tests conducted on the yarns. Overfeed is the governing factor in the process of air texturing. The influence of change in overfeed on the final textured yarn properties is greater than that of any other processing parameter or supply yarn parameter.; The role of water is to combine filaments, thereby presenting fewer free filaments in the airflow. This leads to better three-dimensional displacement of filaments around the central yarn core, which in turn leads to a more uniform yarn structure.; The mechanism of loop formation is redefined based on CFD simulations and high-speed image analysis. As the incoming filaments encounter the plane of air-inlet, they're distributed in one of the six circulation zones and are displaced three dimensionally around the yarn axis as well as pushed out of the nozzle at the same time. Some of the filaments however remain in the non-circulation zone and are carried out of the nozzle and form the core of the air textured yarn structure.; The reasons for the disparity between the present conclusions and earlier reported research are discussed.