Three-Dimensional Model of Whipping Motion in the Processing of Microfibers

Sun, Yize; Zeng, Yongchun; Wang, Xinhou

doi:10.1021/ie101744q

Cited by 53 publications

(44 citation statements)

References 33 publications

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“…For air temperature, the mean air temperature can be measured by the thermocouples with high accuracy, in this study, we focused on the fluctuation of the air temperature; therefore, a low and a medium initial air temperatures of 50 and 100°C were applied in consideration of the limitation of the measuring equipment (hot-wire anemometer). Figure 2 a The profile of air flow field in slot-die melt blowing which was obtained by CFD numerical simulation [29]. b Schematic of devices for measuring the air flow field in slotdie melt blowing.…”

Section: Melt-blowing Setups and Conditionsmentioning

confidence: 99%

Turbulent air flow field in slot-die melt blowing for manufacturing microfibrous nonwoven materials

et al. 2018

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Melt blowing is an industrial approach for producing microfibrous nonwoven materials utilizing high-speed air to attenuate polymer melt. The melt-blowing air flow field which is widely believed to be turbulence determines the process of fiber formation. In this study, the turbulent air flow field in slot-die melt blowing was experimental measured by hot-wire anemometer. The fluctuations of air velocity and temperature, the mean velocity and mean temperature were measured and analyzed; moreover, the relationship between turbulent air flow field and fiber formation in melt blowing was discussed and predicted. In the last part of this paper, the coupling effect of air temperature and velocity was studied tentatively, results showed that air temperature not only had an enhanced effect on velocity, but contributed to the fluctuation of velocity. This work shows that the fluctuating characteristics of air velocity and temperature have dominant effect on fiber motion and the evenness of fiber diameter.

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Section: Melt-blowing Setups and Conditionsmentioning

confidence: 99%

Turbulent air flow field in slot-die melt blowing for manufacturing microfibrous nonwoven materials

et al. 2018

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“…To deepen the understanding on the mechanism of jet thinning in melt-blowing extensive diverse studies have been performed in the last years, covering experimental investigations, e.g., [4,6,11,32,33], combined experimental numerical works, e.g., [26,30,34], as well as numerical computations, e.g., [7,25,29,36]. However, so far, there is an obvious gap between the experimental and numerical results for the achieved fiber thickness in literature.…”

Section: Introductionmentioning

confidence: 99%

Melt-blowing of viscoelastic jets in turbulent airflows: Stochastic modeling and simulation

Wieland

Arne

Marheineke

et al. 2019

Applied Mathematical Modelling

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In melt-blowing processes micro-and nanofibers are produced by the extrusion of polymeric jets into a directed, turbulent high-speed airflow. Up to now the physical mechanism for the drastic jet thinning is not fully understood, since in the existing literature the numerically computed/predicted fiber thickness differs several orders of magnitude from those experimentally measured. Recent works suggest that this discrepancy might arise from the neglect of the turbulent aerodynamic fluctuations in the simulations. In this paper we confirm this suggestion numerically. Due to the complexity of the process direct numerical simulations of the multiscalemultiphase problem are not possible. Hence, we develop a numerical framework for a growing fiber in turbulent air that makes the simulation of industrial setups feasible. For this purpose we employ an asymptotic viscoelastic model for the fiber. The turbulent effects are taken into account by a stochastic aerodynamic force model where the underlying velocity fluctuations are reconstructed from a k-turbulence description of the airflow. Our numerical results show the significance of the turbulence on the jet thinning and give fiber diameters of realistic order of magnitude.

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“…Many researchers [2–6] had studied the air flow field by experiments and computational fluid dynamics, while few did similar research on the polymer flow field. Much work [1, 7–10] done concerning the molten polymer had been based on the basis that the molten polymer was regarded as a whole object, such as a straight cylinder [7], a bead element [8], and a bead‐viscoelastic element [9, 10]. The factors about external morphology of polymer, such as the diameter, were only taken into account, while some properties related to internal molten polymer were beyond consideration.…”

Section: Introductionmentioning

confidence: 99%

“…The molten polymer attenuating mechanism, together with the interaction force between the polymer and high‐velocity gas, was also simplified as the result of tensile force. With the guidance of the above theory, big progress had been made in many ways, such as how to predict fiber diameter [1, 11, 12], describe fiber motions [7–10, 13], and improve fiber or fiber‐web products properties [14–17]. These achievements helped further study and guide the melt‐blowing practice to a great extent.…”

Section: Introductionmentioning

confidence: 99%

Shear flow of molten polymer in melt blowing

Xin

Wang

2012

Polymer Engineering & Sci

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Besides the air flow field, the flow field of molten polymer plays a key role in fiber formation in the melt‐blowing (MB) process. In this article, the flow field of molten polymer was discussed, and its effects on the fiber microstructures were studied through theory and experiments. First, this field was supposed to be a kind of shear flow field. Two equations were introduced and solved. Then, analyzing the solutions combining with the actual melt‐blown practice, we concluded that the distribution profile of this flow field was a series of inverse parabolic in the course of the polymer stream attenuating. Further inferring from this flow pattern, we could also assume that there could have been a novel cross‐sectional microstructures in the melt‐blown fibers. Finally, the comparison experiments concerning the MB and its fibers were designed and carried out. The results indicated that the shear flow field could be qualitatively described by the equations, and the assumptions about the microstructures are basically in agreement with the experimental results. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

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Three-Dimensional Model of Whipping Motion in the Processing of Microfibers

Cited by 53 publications

References 33 publications

Turbulent air flow field in slot-die melt blowing for manufacturing microfibrous nonwoven materials

Turbulent air flow field in slot-die melt blowing for manufacturing microfibrous nonwoven materials

Melt-blowing of viscoelastic jets in turbulent airflows: Stochastic modeling and simulation

Shear flow of molten polymer in melt blowing

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