Numerical investigation on a melt-blowing die with internal stabilizers

2019 ◽  
pp. 152808371986693 ◽  
Author(s):  
Changchun Ji ◽  
Yudong Wang ◽  
Yafeng Sun
Keyword(s):  
Average Velocity ◽  
Fiber Diameter ◽  
Measurement Data ◽  
Melt Blowing ◽  
One Dimensional ◽  
Temperature Decay ◽  
Slot Die ◽  
The Common ◽  
The One ◽  
Peak Value

In order to decrease the fiber diameter and reduce the energy consumption in the melt-blowing process, a new slot die with internal stabilizers was designed. Using computational fluid dynamics technology, the new slot die was investigated. In the numerical simulation, the calculation data were validated with the laboratory measurement data. This work shows that the new slot die could increase the average velocity on the centerline of the air-flow field by 6.9%, compared with the common slot die. Simultaneously, the new slot die could decrease the back-flow velocity and the rate of temperature decay in the region close to the die head. The new slot die could reduce the peak value of the turbulent kinetic energy and make the fiber movements more gradual. With the one-dimensional drawing model, it proves that the new slot die has more edge on the decrease of fiber diameter than the common slot die.

Experimental and numerical analysis of an improved melt-blowing slot-die

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 612-621 ◽  
Author(s):  
Yudong Wang ◽  
Changchun Ji ◽  
Jianping Zhou
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Measurement Data ◽  
Central Area ◽  
Melt Blowing ◽  
Maximum Value ◽  
Die Surface ◽  
Slot Die ◽  
Two Dimensional Flow ◽  
The Common

AbstractIn order to reduce the melt-blowing fiber diameter, an improved slot die with internal stabilizers was designed. The air-flow field of the improved die was measured by a hot wire anemometer. Furthermore, utilizing computational fluid dynamics software, the air flow field from the improved slot die was studied and the work was validated with the laboratory measurement data. The experimental results and numerical simulation data indicate below the die surface, the internal stabilizers play an important role in the velocity distribution of the flow field. Firstly, the improved slot die can increase the velocity and the temperature near the centerline of the flow field and reduce the maximum value of turbulent kinetic energy, compared to the common die. Secondly, the end face of the slot hole has a certain influence on the surrounding flow field and the central area exhibits two-dimensional flow field distribution.

The effect of the geometric structure of the modified slot die on the air field distribution in the meltblowing process

2021 ◽  
pp. 004051752110351
Author(s):  
Yudong Wang ◽  
Yiping Qiu ◽  
Changchun Ji ◽  
Xinhou Wang ◽  
Fuwang Guan
Keyword(s):  
Inclination Angle ◽  
Fiber Diameter ◽  
Block Structure ◽  
Air Velocity ◽  
Temperature Decay ◽  
Block Height ◽  
Slot Die ◽  
Airflow Field ◽  
The Common ◽  
Block Width

In order to reduce the fiber diameter and the energy consumption in the meltblowing process, a modified slot die with two blocks was designed in this article. The numerical calculation and the experimental verification of the airflow field under the modified slot die were carried out, and the effect of the block structure parameters on the air field was investigated. The research results indicate that compared to the common slot die, the modified slot die with the blocks could increase the velocity on the spinning line and reduce the rate of the temperature decay on the spinning line. When the block width and the block inclination angle lower, and the block height expands, it could increase the peak of the air velocity, the temperature and the turbulence intensity on the center line of the air field under the modified slot die. The average velocity on the spinning line of the modified die under the conditions of block width = 20 mm, block height = 30 mm and block inclination angle = 60° is the highest.

scholarly journals The development of biofilm architecture

2016 ◽  
Vol 472 (2188) ◽  
pp. 20150798 ◽  
Author(s):  
A. C. Fowler ◽  
T. M. Kyrke-Smith ◽  
H. F. Winstanley
Keyword(s):  
Bacterial Biofilm ◽  
Governing Equations ◽  
Biofilm Growth ◽  
One Dimensional ◽  
Direct Numerical Solution ◽  
The Common ◽  
Common Observation ◽  
The Stability ◽  
The One ◽  
A Free Boundary Problem

We extend the one-dimensional polymer solution theory of bacterial biofilm growth described by Winstanley et al . (2011 Proc. R. Soc. A 467 , 1449–1467 ( doi:10.1098/rspa.2010.0327 )) to deal with the problem of the growth of a patch of biofilm in more than one lateral dimension. The extension is non-trivial, as it requires consideration of the rheology of the polymer phase. We use a novel asymptotic technique to reduce the model to a free-boundary problem governed by the equations of Stokes flow with non-standard boundary conditions. We then consider the stability of laterally uniform biofilm growth, and show that the model predicts spatial instability; this is confirmed by a direct numerical solution of the governing equations. The instability results in cusp formation at the biofilm surface and provides an explanation for the common observation of patterned biofilm architectures.

Experimental Study on the Pollutants Release Characteristics During Combustion of Lean Coal with Different Coal Rank

2012 ◽  
Vol 518-523 ◽  
pp. 2143-2146
Author(s):  
Yong Zheng Wang ◽  
Xiu Juan Li ◽  
Su Le Tian ◽  
Chun Mei Lu
Keyword(s):  
Great Influence ◽  
Coal Rank ◽  
One Dimensional ◽  
Weighted Means ◽  
No Release ◽  
Lean Coal ◽  
The One ◽  
Coal Property ◽  
Furnace Height ◽  
Peak Value

In this paper, the characteristics of SO2 and NO release during combustion of lean coal with different coal rank were experimentally studied in the one-dimensional furnace for pulverized coal combustion. The results showed: The coal property and proportion of the component coals have great influence on the characteristics of SO2 and NO release. The releasing concentration of SO2 and NO distributing along the furnace height is generally between that of component coals, and the releasing characteristics of SO2 and NO would be more near to that of the larger proportion coal. The measuring value of the formation concentration of SO2 and NO are different from the calculating value based on the weighted means of the component coals to a certain extent. While the different coal are added to lean coal, the time corresponding with peak value releasing concentration of SO2 and NO is different.

The backward problem of parabolic equations with the measurements on a discrete set

2020 ◽  
Vol 28 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Jin Cheng ◽  
Yufei Ke ◽  
Ting Wei
Keyword(s):  
Parabolic Equations ◽  
Numerical Approximation ◽  
Cross Validation ◽  
Continuation Method ◽  
Measurement Data ◽  
Initial Value ◽  
One Dimensional ◽  
Backward Problem ◽  
The One ◽  
Validation Rule

AbstractThe backward problems of parabolic equations are of interest in the study of both mathematics and engineering. In this paper, we consider a backward problem for the one-dimensional heat conduction equation with the measurements on a discrete set. The uniqueness for recovering the initial value is proved by the analytic continuation method. We discretize this inverse problem by a finite element method to deduce a severely ill-conditioned linear system of algebra equations. In order to overcome the ill-posedness, we apply the discrete Tikhonov regularization with the generalized cross validation rule to obtain a stable numerical approximation to the initial value. Numerical results for three examples are provided to show the effect of the measurement data.

scholarly journals Closed-Form Exact Solutions for the Unforced Quintic Nonlinear Oscillator

2017 ◽  
Vol 2017 ◽  
pp. 1-14
Author(s):  
Augusto Beléndez ◽  
Enrique Arribas ◽  
Tarsicio Beléndez ◽  
Carolina Pascual ◽  
Encarnación Gimeno ◽  
...  
Keyword(s):  
Exact Solutions ◽  
Closed Form ◽  
Elliptic Integral ◽  
First Integral ◽  
Jacobi Elliptic Function ◽  
Complete Elliptic Integral ◽  
One Dimensional ◽  
The Common ◽  
The One ◽  
Two Parameters

Closed-form exact solutions for the periodic motion of the one-dimensional, undamped, quintic oscillator are derived from the first integral of the nonlinear differential equation which governs the behaviour of this oscillator. Two parameters characterize this oscillator: one is the coefficient of the linear term and the other is the coefficient of the quintic term. Not only the common case in which both coefficients are positive but also all possible combinations of positive and negative values of these coefficients which provide periodic motions are considered. The set of possible combinations of signs of these coefficients provides four different cases but only three different pairs of period-solution. The periods are given in terms of the complete elliptic integral of the first kind and the solutions involve Jacobi elliptic function. Some particular cases obtained varying the parameters that characterize this oscillator are presented and discussed. The behaviour of the periods as a function of the initial amplitude is analysed and the exact solutions for several values of the parameters involved are plotted. An interesting feature is that oscillatory motions around the equilibrium point that is not at x=0 are also considered.

Coherence and Continuity: A Study in Comparative Codification

1987 ◽  
Vol 22 (2) ◽  
pp. 184-218 ◽  
Author(s):  
Celia Wasserstein Fassberg
Keyword(s):  
Common Law ◽  
Characteristic Mode ◽  
Historical Process ◽  
One Dimensional ◽  
Conceptual Coherence ◽  
Legal Provisions ◽  
The Common ◽  
Internal Coherence ◽  
The One ◽  
Linguistic Fact

The English common law is frequently referred to as a seamless web; continental lawyers tend rather to think of law in terms of internal coherence and consistency. This is not merely a linguistic fact, and the terms are not simply interchangeable. Each reflects the characteristic mode of thought and of development in its respective system: the common law constantly and gradually emerging as a cumulative historical process; continental law stemming from, and in every case ultimately resting on interpretation of, codes, the product of a moment in history. Thus, although they are both capable of denoting the same idea of wholeness, each term has a slightly different connotative emphasis, the one stressing historical coherence and the other emphasising conceptual coherence.This is but one example of the proposition that institutions can not be imported wholesale, that foreign legal provisions, and terms of thought and reference, have to be evaluated beyond their immediate superficial appearance before they may be adopted or used as measures for local purposes. All such institutions have both a historical and a contextual significance which makes comparison on the level of one-dimensional questions such as, “Which is the better rule or the more attractive term?” meaningless.

scholarly journals Ensemble Laser Diffraction for Online Measurement of Fiber Diameter Distribution during the Melt Blowing Process

2004 ◽  
Vol os-13 (2) ◽  
pp. 1558925004os-13 ◽  
Author(s):  
Eric M. Moore ◽  
Robert L. Shambaugh ◽  
Dimitrios V. Papavassiliou
Keyword(s):  
Fiber Diameter ◽  
Pilot Scale ◽  
Laser Diffraction ◽  
Diameter Distribution ◽  
Online Measurement ◽  
Melt Blowing ◽  
Scale Unit ◽  
Slot Die ◽  
Online Measurements ◽  
Fiber Diameter Distribution

Online measurements of the fiber diameter distribution during a melt blowing process were taken using a new laser diffraction technique. This technique measured both the attenuation of the fibers as well as entanglement of the fibers into bundles at large distances from the die. A pilot scale unit with a 20.3 cm (8 inch) slot die was used for the studies. Commercial polypropylene polymer was used. Both the spin-line attenuation and fiber bundling were measured as a function of position both below and across the die face.

scholarly journals BIC in waveguide arrays

2021 ◽  
Vol 255 ◽  
pp. 07001
Author(s):  
Vladimír Kuzmiak ◽  
Jiří Petráček
Keyword(s):  
Bound State ◽  
Coupled Mode Theory ◽  
One Dimensional ◽  
Waveguide Arrays ◽  
Coupled Mode ◽  
Simple Theoretical Model ◽  
The Common ◽  
The One ◽  
Symmetry Protected ◽  
The Continuum

We propose a simple theoretical model based on the coupled-mode theory which allows to calculate the spectral properties and transmittance of the one-dimensional waveguide structures. The model was verified on the common coupled-waveguide array in which the existence of the symmetry-protected bound state in the continuum (BIC) was confirmed experimentally by Plotnik et al. [Phys. Rev. Lett. 107, 28-31 (2011)]. The method can be extended to topologically nontrivial lattices to explore the properties of the BICs protected by time-reversal symmetry.

Evaluation and Enhancement of a One-Dimensional Performance Analysis Method for Centrifugal Compressors

2014 ◽  
Author(s):  
Enrico Klausner ◽  
Uwe Gampe
Keyword(s):  
Performance Analysis ◽  
Performance Prediction ◽  
Standard Procedure ◽  
Flow Analysis ◽  
Measurement Data ◽  
Theoretical Models ◽  
Analysis Method ◽  
Centrifugal Compressors ◽  
One Dimensional ◽  
The One

The one-dimensional flow analysis along a mean streamline is an appropriate and established procedure for initial design and performance analysis of turbomachinery. One such method for performance analysis of centrifugal compressors was published by Aungier in the 1990s. The latest description of Aungier’s performance prediction model was applied to a set of centrifugal compressor stages published in literature. For each test case the whole performance map was calculated and compared with measurement data. The calculation results correspond well with measured data over a wide operating range. However, near choke or stall the mean streamline performance prediction deviates from measurements. After evaluation of this “standard” mean streamline model specific loss correlations, e.g. for choking, incidence and shock losses were replaced by theoretical models. The aim was to implement a more physical based loss model which is able to predict the performance of compressor stages outside the limits of the standard procedure. The modified procedure was again validated against measurements of the above mentioned compressor stages. The modified procedure gives a better prediction of operating performance and behavior. Shortcomings of the procedure are still the overestimation of vaneless diffuser losses at low mass flow rates and the uncertainty in prediction of choke limit. In conclusion recommendations for advancement of the one-dimensional performance analysis method are given.

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