An air-jet flow field model of the dual slot die in the melt blowing nonwoven process is proposed and solved numerically with the finite difference method. The effects of dual slot dic design parameters on velocity and temperature distributions in the melt blowing flow field are investigated. The computation results of the distributions of the x-components of air velocity and air temperature coincide well with our experimental data. The results show that a smaller angle α, a larger slot width e, and a narrower head width f will all result in higher x-components of air velocity and higher e air temperatures, which are beneficial to the air drawing of the polymer melt and thus to reduced fiber diameter. The results show the great potential of this research for computer-assisted design in the melt blowing nonwoven technology.

将纷繁多样的衣架型模头设计理论归结为解析方法和数值方法两大类，综述了不同设计方法的设计原理以及各种设计的优点和局限性。

研究了聚合物熔体在衣架型模头中的等温流动。采用幂律模型描述该熔体的流变行为，通过三雏有限元方法对此流动进行模拟，从而得到其速度场的分布情况，并且着重讨论了衣架型模头的几何形状对速度场分布的影响，特别是对出口宽度方向速度均匀性的影响。

A three-dimenslonal finite element model is developed to deal with the polymeric liquid flow in coat-hanger die. This model Is used to predict the flow behavior of the 2% CMC/watsr solution in the coat-hanger die with linearly taper manifolds and Its validity Is experimentally verified quantitatively and qualitatively by using Laser Doppler Veloclmetry and Particle Image Veloclmetry respectively.

The air permeability of airbag fabrics was measured at high pressure differentity up to 200 kPa, It was found that permeability varied with pressure differential nonlineariy. The relationship between air permeability and the pressure differential was fitted well with power law curve. The study revealed that the coefficient c and exponent b in the power law equation had a strong correlation with porosity, which was chosen to characterize the airbag fabrics.