旋流喷嘴对不同线密度纱线的作用机制

为研究旋流喷嘴纺纱方法对不同线密度纱线的减羽效果，借助计算流体软件模拟旋流喷嘴内部气流特性及不同线密度纱线在气流作用下的压强与速度分布，并用纺纱试验进行验证。模拟结果表明，进入纱道后的气流沿顺时针方向分别朝纱道入口及出口方向运动，纱线表面毛羽主要受到气流的包裹力和由于纱线自转而产生的相对包裹力作用。气流的旋转特性使得纱道管壁附近的压强高于轴线附近，因此不同线密度纱线的表面所处涡流的位置不同，受到的气流包裹力也不同。纱线线密度较小，表面受到的压强分布密集，x、y、z 向速度波动较大，其中20 tex 纱线表面的压强和速度分布情况优于10、30、40 tex 的。研究结果表明，旋流喷嘴压强在0.2 MPa 下，对20 tex 大麻/ 棉（40/60）的减羽效果最优，达到了87.6%，与数值模拟结果一致。

Mechanism of swirl nozzle on yarns with different linear densites

In order to study the effect of swirl nozzle spinning method on yarns of different linear density, vortex nozzle internal airflow characteristics, air pressure and velocity distribution of yarns with different linear densitesunder the effect of vortex were simulated by means of computational fluid sojtware, and spinning experiment was designed to validate the simulation result. Theresults show airflowsmove clockwise toward the yarn channel inlet and outlet direction, respectively,after yarns enter into the yarn channel, and the yarn surface hairiness number are mainly decreased by air wrapped force and the relative revolving action because of theself-twisting of the yarn.The pressure near the pipe wall is higher than yarn channel axis pressure because of the airflow rotating feature, therefore pressure distribution on the surface of yarns of different linear densites yarns and wrapped force are different. Yarn linear density is smaller, the pressure distribution of yarn surface is more intensive, and velocity along x, y andz axis have relatively large fluctuations. The pressure and velocity distribution on thesurface of 20 tex yarn arebetter than that of10 tex, 30 tex and 40 tex yarns. The experimental results show that the hairiness reduction ratio of 20 tex yarn madefrom 40 % of hemp and 60% of cotton reaches 87.6% under 0.2 MPa pressure, whichis consistent with the results of numerical simulation.