Numerical study on the principle of yarn formation in murata air-jet spinning

Abstract

A realizable k-ε turbulence model was adopted to study the airflow characteristics inside the two nozzles including the slotting-tube of Murata air-jet spinning (MJS). Actions of the two nozzles and the accepted principle of yarn formation were both discussed. The results show that some factors in the first nozzle, such as weak opposite swirling balloon in upstream, of the jet orifice, vortex breakdown in downstream, of the jet orifice and opposite direction airflows between the grooves and the twisting chamber, do good to produce longer wrapper fibers and form twist difference between the edge fibers and the core ones. The airflow in the second nozzle rotates in the opposite direction to that in the first nozzle, to untwist the swirling balloon that formed by the first nozzle. On the other hand, simulation results well supported the theoretical analysis of the principle of the yarn formation proposed by Stalder and Krause. © 2007 The Textile Machinery Society of Japan.