熔喷气流场与纤维运动及纤维直径的数学计算

Melt-Blowing Air Flow Field & Mathematic Calculation for Fiber Motion and Fiber Diameter

对狭槽模头下熔喷气流场进行了数值模拟,得到气流的流线以及速度矢量分布,采用高速摄像技术捕捉狭槽喷嘴下的纤维运动轨迹,并对纤维运动的特征及其与气流场特征之间关系进行探讨,结果显示纤维的二维运动特征是由气流场的二维特征决定的。因为熔喷过程中纤维运动速度很高,测量设备很难在线测量熔喷过程中的纤维直径的变化规律,本文建立了一种可以计算纤维直径的数学方法,该方法只凭借纤维轨迹信息就能在线计算纤维直径的变化规律。首先对这种数学方法做统一的理论推导,之后在理论推导基础上对纤维模型进行离散处理,经过离散处理后可得到更精确的数学解,将数学预测的结论与实验获得的纤维直径进行对比,结果表明数学预测与实验结论较为吻合。

The melt-blowing air flow field under slot-die was numerically simulated,and the flow line and velocity vector distribution of air flow were gained.Fiber motion path was captured by high-speed photography technology,and the relationship between air flow field features and fiber motion features was discussed.The results showed that two-dimensional motion feature of fibers was determined by corresponding two-dimensional characteristics of air flow field.Since fiber velocity in melt-blowing process was high,online measurement of fiber diameter change rule in the melt blowing process by measuring equipment was unrealizable.In this study,a mathematic method was built to calculate fiber diameter,which can calculate fiber diameter change rule on line just according to the fiber path information.Firstly,the unified theoretical derivation was accomplished,and then discrete treatment was conducted for the fiber model on the basis of theoretical derivation.After disperse treatment,more precision mathematic solutions could be gained.The mathematically predicted conclusion was compared with the fiber diameter acquired by the experiment.The result showed that the mathematic prediction is consistent with the experimental conclusion.