Turbulence of melt-blowing airflow field: Comparison of a convergent jet and a typical free jet

2021 ◽  
Vol 33 (7) ◽  
pp. 075107
Author(s):  
Ying Yang ◽  
Hui Huang ◽  
Yongchun Zeng
Keyword(s):  
Melt Blowing ◽  
Free Jet ◽  
Airflow Field

Study on airflow field and fiber motion with new melt blowing die

2019 ◽  
Vol 59 (6) ◽  
pp. 1182-1189 ◽  
Author(s):  
Wanli Han ◽  
Sheng Xie ◽  
Jing Shi ◽  
Xinhou Wang
Keyword(s):  
Melt Blowing ◽  
Fiber Motion ◽  
Airflow Field

Effect of slot end faces on the three-dimensional airflow field from the melt-blowing die

2020 ◽  
Vol 40 (7) ◽  
pp. 607-613
Author(s):  
Yudong Wang ◽  
Jianping Zhou
Keyword(s):  
Numerical Calculation ◽  
Flow Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Central Area ◽  
Computational Domain ◽  
Melt Blowing ◽  
Slot Die ◽  
Calculation Results ◽  
Airflow Field

AbstractIn order to investigate the effect of the slot ends of the melt-blowing die on the three-dimensional airflow field distribution and the fiber draft, the numerical calculation was carried out. The computational domain of the slot die was established with Gambit, and the flow field was calculated using FLUENT. Compared with the experimental data collected by a hot-wire anemometer, the numerical calculation results are credible. The results show that the slot end face has a certain influence on the three-dimensional flow field distribution under the melt-blowing die. The air velocity and temperature in the center region are quite different from those near the slot-end face. As the distance from the center of the flow field increases, the velocity and temperature on the spinning line begin to decrease. The velocity and temperature distributions of the spinning lines in the central area and nearby areas are almost the same; the temperature and velocity values on the spinning lines near the slot end are the lowest. The distribution characteristics of the three-dimensional airflow field could affect the uniformity of the fiber diameter and the meltblowing products.

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.

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

Simulations of a Turbulent Free Jet

2014 ◽  
Vol 8 (5) ◽  
pp. 820
Author(s):  
Saad Ahmed ◽  
Bharath Raghavan
Keyword(s):  
Free Jet

Free-jet expansions from laser-vaporized planar surfaces

1976 ◽  
Author(s):  
M. COVINGTON ◽  
G. LIU ◽  
K. LINCOLN
Keyword(s):  
Free Jet ◽  
Planar Surfaces
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