scholarly journals Lateral Diffusion of a Free Air Jet in Slot-Die Melt Blowing for Microfiber Whipping

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 788 ◽  
Author(s):  
Sheng Xie ◽  
Wanli Han ◽  
Xufan Xu ◽  
Guojun Jiang ◽  
Baoqing Shentu
Keyword(s):  
High Speed ◽  
Lateral Diffusion ◽  
Polymer Melt ◽  
Nonwoven Material ◽  
Fiber Formation ◽  
High Speed Photography ◽  
Melt Blowing ◽  
Lateral Velocity ◽  
Air Jet ◽  
Slot Die

In melt blowing, microfibrous nonwoven material is manufactured by using high-speed air to attenuate polymer melt. The melt-blown air jet determines the process of polymer attenuation and fiber formation. In this work, the importance of lateral velocity on the fiber was first theoretical verified. The lateral diffused characteristic of the air flow field in slot-die melt blowing was researched by measuring the velocity direction using a dual-wire probe hot-wire anemometer. Meanwhile, the fiber path was captured by high-speed photography. Results showed that there existed a critical boundary of the lateral diffusion, however, air jets in the x–z plane are a completely diffused field. This work indicates that the lateral velocity in the y–z plane is one of the crucial factors for initiating fiber whipping and fiber distribution.

scholarly journals Measurement and Comparison of Melt-Blowing Airflow Fields: Nozzle Modifications to Reduce Turbulence and Fibre Whipping

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 719
Author(s):  
Ying Yang ◽  
Yongchun Zeng
Keyword(s):  
Turbulence Intensity ◽  
Temperature Fluctuation ◽  
High Speed ◽  
Aerodynamic Force ◽  
High Speed Photography ◽  
Melt Blowing ◽  
Fluctuation Intensity ◽  
Slot Die ◽  
Turbulent Airflow ◽  
Airflow Field

In the melt-blowing process, micro/nanofibrous nonwovens are attenuated and formed through aerodynamic force in a turbulent airflow field. In this work, two types of airflow-directors were added under a common melt-blowing slot-die nozzle to obtain modified airflow fields. The effect of airflow-directors on time-averaged characteristics, turbulence intensity, and temperature fluctuation intensity are achieved through the simultaneous measurement of fluctuating velocity and fluctuating temperature using a two-wire probe hot-wire anemometer. Moreover, the influence of airflow-directors on fibre oscillations are also investigated through high-speed photography. The distribution of turbulence intensity and temperature fluctuation intensity reveals the characteristics of fluctuating airflow fields formed by different melt-blowing slot-die nozzles. Through the analyses of airflow characteristics and fibre oscillations, we can find that the arrangement of airflow-directors has a great impact on both turbulence distribution and fibre oscillation.

Simulation of jet velocity in the melt-blowing process using the coupled air–polymer model

2018 ◽  
Vol 89 (16) ◽  
pp. 3221-3233 ◽  
Author(s):  
Xibo Hao ◽  
Hui Huang ◽  
Yongchun Zeng
Keyword(s):  
High Speed ◽  
Flow Model ◽  
Processing Parameters ◽  
High Speed Photography ◽  
Critical Factors ◽  
Polymer Model ◽  
Melt Blowing ◽  
Two Phase ◽  
Jet Velocity ◽  
Jet Velocities

The polymer jet velocity is one of the most basic and critical factors in the melt-blowing process and has always been difficult to measure online. Much effort has been made on the numerical prediction of the jet velocity. However, little work has involved the complex interaction between the air flow and the polymer. Here, the Level-Set method is used to develop the coupled air–polymer two-phase flow model, and to simulate the polymer jet motion in the melt-blowing process considering the coupled effect of the air and polymer. Meanwhile, high-speed photography is adopted in the experiments to verify the simulation results. The x- and y-components of the jet velocities and the whipping amplitude of the jet motion are discussed. The rapid increase of jet velocity and the decrease of jet diameter show that most attenuation of the polymer jet occurred within a distance close to the die (10 mm). Based on the model, the effects of the processing parameters on the jet velocity are examined numerically.

A Geometry Method for Calculating the Fiber Diameter Reduction in Melt Blowing

2014 ◽  
Vol 893 ◽  
pp. 87-90 ◽  
Author(s):  
Sheng Xie ◽  
Yong Chun Zeng
Keyword(s):  
High Speed ◽  
Fiber Diameter ◽  
Mechanical Analysis ◽  
Diameter Distribution ◽  
High Speed Photography ◽  
Melt Blowing ◽  
Ultrafine Fibers ◽  
Online Measurements ◽  
Fiber Diameter Distribution ◽  
Diameter Reduction

Melt blowing is one of the important methods for producing ultrafine fibers. The production of melt blowing is the nonwoven. Fiber diameter has crucial effect on the property of the nonwovens. In the melt-blowing process, many achievements have been published on the fiber diameter distribution along the spinning line. Note that all the results were obtained by methods of mechanical analysis, online measurements through high-speed photography and offline measurements from the production of nonwoven. In this study, a new method for calculating the fiber diameter distribution along the spinning line near the die face was revealed. This method was based on the geometry of the fiber path in the melt-blowing process. The fiber diameter reduction was calculated by this method and then compared with the experimental results obtained by other researchers. The results show that the proposed method is feasible.

Gas-Assisted Droplet Impact on a Solid Surface

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Andres J. Diaz ◽  
Alfonso Ortega
Keyword(s):  
Solid Surface ◽  
High Speed ◽  
Liquid Droplet ◽  
High Speed Photography ◽  
Droplet Deformation ◽  
Droplet Spreading ◽  
Carrier Gas ◽  
Air Jet ◽  
Vof Model ◽  
Theoretical Predictions

An experimental, numerical, and theoretical investigation of the behavior of a gas-assisted liquid droplet impacting on a solid surface is presented with the aim of determining the effects of a carrier gas on the droplet deformation dynamics. Experimentally, droplets were generated within a circular air jet for gas Reynolds numbers Reg = 0–2547. High-speed photography was used to capture the droplet deformation process, whereas the numerical analysis was conducted using the volume of fluid (VOF) model. The numerical and theoretical predictions showed that the contribution of a carrier gas to the droplet spreading becomes significant only at high Weo and when the work done by pressure forces is greater than 10% of the kinetic energy. Theoretical predictions of the maximum spreading diameter agree reasonably well with the experimental and numerical observations.

Prediction of Fiber Diameter of Melt Blown Nonwovens Produced by Sharp Die Using Neural Network Theory

2011 ◽  
Vol 101-102 ◽  
pp. 543-546
Author(s):  
Bo Zhao
Keyword(s):  
Neural Network ◽  
Fiber Diameter ◽  
Polymer Melt ◽  
Processing Parameters ◽  
Ann Model ◽  
Melt Blowing ◽  
Melt Temperature ◽  
Nonwoven Fabrics ◽  
Air Jet ◽  
Neural Network Theory

Melt blowing is known for directly converting polymer resin into nonwoven fabrics of microfibers. The fiber diameter of melt blown nonwoven fabrics is strongly influenced by the air jet flow field developed from the sharp die. The dual slot sharp die is often used to yield polymer fibers in this process. The objective of this paper is to investigate the fiber diameter of melt blowing nonwovens produced by sharp die using an artificial neural network model. The fiber diameter of melt blowing nonwoven is mostly influenced by processing parameters (polymer flow rate, polymer melt temperature, initial air velocity, die-to-collector distance and initial air temperature). By analyzing the results obtained with the aid of the ANN model, the effects of melt blowing process parameters on the fiber diameter can be predicted. The results demonstrate that ANN model is a effective and a excellent method for predictors.

Modeling the Air-Jet Flow Field of a Dual Slot Die in the Melt Blowing Nonwoven Process

2004 ◽  
Vol 74 (11) ◽  
pp. 1018-1024 ◽  
Author(s):  
Ting Chen ◽  
Xinhou Wang ◽  
Xiubao Huang
Keyword(s):  
Flow Field ◽  
Jet Flow ◽  
Melt Blowing ◽  
Air Jet ◽  
Slot Die

Effects of the die Parameters on the Air Flow Field from a Dual Slot Melt Blowing Die

2011 ◽  
Vol 332-334 ◽  
pp. 1347-1351
Author(s):  
Xu Chuan ◽  
Li Li Wu
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Air Flow ◽  
Jet Flow ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Air Jet ◽  
Slot Die ◽  
The Mean

In this paper, the air jet flow field model for the dual slot die is established. The flow field from the blunt die was found to exhibit that as the jet angle becomes sharper, width of the die slot and distance between the inside edges of both jets more narrow, the mean velocity under the die increases.

The Effect of Air Pressure on the Evolution of Fiber Path in Melt-Blowing Process

2014 ◽  
Vol 852 ◽  
pp. 496-500
Author(s):  
Sheng Xie ◽  
Yong Chun Zeng
Keyword(s):  
High Speed ◽  
Air Pressure ◽  
High Speed Camera ◽  
Pressure Condition ◽  
Melt Blowing ◽  
Attenuation Effect ◽  
Ultrafine Fibers ◽  
Important Method ◽  
Slot Die ◽  
Fiber Path

Melt blowing is an important method for producing ultrafine fibers. In melt blowing process, compared to the studies on the fiber path at a certain air pressure condition, much less has been done on searching the evolution of the fiber paths at different air pressures. In this study, a high-speed camera was used to capture the fiber paths below a slot die and a swirl die in the melt-blowing process. The evolution of the fiber paths was captured. This paper first shows the evolution of the fiber paths at different air pressures, which is useful to further understand the attenuation effect on the fiber in the melt-blowing process.

Optimum Design for the Dual Slot Die Parameters of Melt Blowing Process

2013 ◽  
Vol 796 ◽  
pp. 272-276
Author(s):  
Ting Ting Cheng ◽  
Chuan Xu ◽  
Li Li Wu ◽  
Ting Chen
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Slot Width ◽  
Design Parameters ◽  
Orthogonal Experimental Design ◽  
Computer Assisted ◽  
Range Analysis ◽  
Melt Blowing ◽  
Air Jet ◽  
Slot Die

Melt blowing process can produce superfine fibers. In this process, the polymer is drawn by the high velocity hot air jets from the dual slot die. The die parameters have great effects on the fiber diameter. In this paper, the die parameters of the dual slot die in an industrial melt blowing equipment are studied using the orthogonal experimental design method. Three parameters namely the inset distance, slot width and slot angle are considered. Each parameter has three levels. Nine sizes of dual slot dies with different design parameters are numerically simulated using the established air flow field model of melt blowing process. Distributions of air velocity and air temperature of nine air jet flow fields are obtained. Effects of the three parameters are studied with range analysis and variance analysis. The results show that the inset distance and slot width have significant effects on the air flow field while effect of the slot angle is unremarkable. Finally the optimal die parameters are obtained. The results lay the theoretical foundation for further studies on the computer assisted design for the dual slot die in the melt blowing process.

Sign in / Sign up

Export Citation Format

Share Document