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

Abstract

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.

Formation Mechanism of Fibrous Web in the Solution Blowing Process

“…We have mentioned the uniformity difference of the basis weight in the MD and CD during MB in our previous work. 15 − 18 In this study, we also found a similar distribution of the basis weight during SB.…”

“…In this study, the air velocity should be simulated in advance. In some of the published simulations, − the fluent module of ANSYS software was employed to simulate the air velocity. To simulate the fibrous web on the collector, once the free end of the solution reached a given XY plane (a hypothetical collector), its XZ coordinates and diameter were frozen, whereas its Y coordinate was varied following the translational motion of the collector in the Y direction.…”

Airflow, Fiber Dynamic Whipping, and Final Fiber Diameter in Flush Sharp-Die Melt Blowing with Different Air-Slot Widths

“…In Fluent, the standard k -ε model , was used to calculate the two-dimensional flow field of the melt-blown slot dies. At the same time, the turbulence model parameters C ε1 and C ε2 were modified to 1.24 and 2.05, respectively. , …”

“…Chen et al numerically studied the effects of slot-die design parameters on air velocity and temperature distributions in the melt-blown flow field. The CFD method has been more and more applied into designing or optimizing a melt-blown die structure. ,− Sun and Wang used the single-objective genetic algorithm and the CFD technology to achieve an optimized slot die. Wang et al ,− designed an improved melt-blown die with stabilizing pieces by CFD simulation.…”

“…Wang et al ,− designed an improved melt-blown die with stabilizing pieces by CFD simulation. Wang et al numerically investigated that adding an auxiliary nozzle was helpful to further decrease the fiber diameter. Hassan et al found that applying air constrictors around the primary air jets could keep the maximum air velocity and temperature in a longer distance.…”