Abstract:

Melt-blown non-woven fabric has many excellent uses in filtration, bacteria resistance, adsorption, waterproofing and so on, with the potential for a vast future market. The stretching process of polymer to produce melt-blown non-woven fabric is too complex and rapid to be observed experimentally. Therefore, a computational fluid dynamics (CFD) method is widely used in the analysis of this process including the analysis of the flow channels in the dies and the jet flow field under the spinneret. The jet flow field analysis is the most extensively examined, which provides solutions for optimizing the spinneret structures and the jet flow field. This article briefly introduced the principles and characteristics of melt- blowing, and reviewed the research progress of CFD simulations in this area. Currently, the CFD simulations of melt-blowing processes were generally based on airflows in the jet flow field without considering the effect of viscous polymer fibers on them. However, the viscous polymer fibers vibrated under conditions of high velocity and high-temperature airflows, and these effects on the jet flow field should not be neglected. The key problem in melt-blowing was to reduce the diameters of the polymer fibers and improved the quality of the melt-blown non-woven fabric. Consequently, the research should concentrate on the fibers flow field and not the airflow field. The viscous polymer fibers that flow in the melt-blowing process were effected by the high velocity and temperature of the airflows in the jet flow field as the phase was changed from liquid to solid. Although CFD simulations were widely utilized in modeling the melt-blowing process, the study of the flow field simulation of polymer fibers in a molten state had not yet been carried out. This problem remained and should be studied in the future.

Key words: melt-blown, computational fluid dynamics, jet flow field, polymer stretching

摘要：

聚丙烯非织造布采用熔喷工艺制成，在过滤、阻菌、吸附、防水等方面性能优异，有着非常广阔的市场前景。熔喷工艺中的聚合物拉伸过程复杂且迅速，难以用实验观察。因此，为降低熔喷布生产成本，提高成品质量，计算流体力学（computational fluid dynamics, CFD）方法被广泛应用于该工艺过程分析之中，包括模头中的流道分析、喷射流场分析等。其中，喷射流场分析是主要应用方向，可为喷丝板结构优化、喷射流场优化等问题提供解决方案。本文简要介绍了聚丙烯非织造布熔喷工艺原理及其特点，主要对该领域中应用CFD模拟的相关研究进展进行了综述。文中指出，目前熔喷过程的CFD模拟一般基于喷射流场中的气流，没有考虑黏性聚合物纤维对其影响。然而，黏性聚合物纤维在高速高温气流条件下会发生振动，对射流流场的影响不容忽视。熔喷非织造布的关键问题是减小聚合物纤维的直径，提高熔喷非织造布的质量。因此，研究的重点应逐渐由气流场转变为纤维流场。虽然CFD已被广泛应用于熔喷过程模拟，但熔融状态下聚合物纤维流场模拟研究仍需要在未来的工作中进行展开。

关键词: 熔喷, 计算流体力学, 熔喷流场, 聚合物拉伸