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.

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.

scholarly journals Air Velocity, Air Temperature, Fiber Vibration and Fiber Diameter Measurements on a Practical Melt Blowing Die

2004 ◽  
Vol os-13 (3) ◽  
pp. 1558925004os-13 ◽  
Author(s):  
Eric M. Moore ◽  
Dimitrios V. Papavassiliou ◽  
Robert L. Shambaugh
Keyword(s):  
Fiber Diameter ◽  
Diameter Distribution ◽  
Process Conditions ◽  
Air Velocity ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Slot Die ◽  
On Line ◽  
The Mean ◽  
Light Absorbance

Numerous measurements were taken during the operation of a practical melt blowing slot die. On-line measurements were taken of the mean velocity and temperature of the air jets. Also, on-line measurements of fiber vibration amplitude were done. Off-line measurements were taken to determine fiber diameter distributions in the nonwoven webs. The light absorbance of these non-woven mats was measured and related to fiber diameter distribution and mat basis weight. Process conditions were varied across the operating range of the die to produce a variety of finished mats. It was found that the mean air velocity and temperature decayed in a manner similar to that observed in both laboratory-scale melt blowing dies and (more generally) in rectangular jets. Fiber vibrations were found to be strongly dependent on operating temperature and air flow rate. The fiber light absorbance correlated well with the projected area of the fibers present in the mat.

Numerical Study on the Polymer Drawing of the Unsymmetrical Air Flow Field in Melt Blowing Process

2013 ◽  
Vol 796 ◽  
pp. 264-267
Author(s):  
Yao Ma ◽  
Hua Jun Chen ◽  
Ting Chen ◽  
Li Li Wu
Keyword(s):  
Flow Field ◽  
Air Temperature ◽  
Fiber Diameter ◽  
Air Flow ◽  
Transverse Displacement ◽  
Air Velocity ◽  
Melt Blowing ◽  
Air Jets ◽  
Hot Air ◽  
Slot Die

Melt blowing is a typical nonwoven process for producing superfine fibers. In this process, the high velocity hot air jets attenuate the polymer melt into superfine fibers. Therefore, the fiber diameter is strongly affected by the air flow field. Dual slot die is one of the widely used melt blowing dies. Hot air emits from the two slots symmetrically. What will happen to the polymer drawing if the air jets are unsymmetrical? In this paper, the unsymmetrical air flow field of the dual slot die in melt blowing process is simulated numerically. The distributions of air velocity and air temperature are obtained. The polymer drawing model is then solved with the aid of the simulation results of air velocity and air temperature. The diameter and transverse displacement of the threadline along the spinline is achieved. The result shows that the threadline diameter of unsymmetrical air flow field is larger than that of the symmetrical air flow field and the threadline tends to deflect because of the unsymmetrical air jets. This paper helps to indicate the research direction for further decreasing the fiber diameter of melt blown nonwoven fabrics.

Experimental investigation on the three-dimensional flow field from a meltblowing slot die

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 724-732
Author(s):  
Changchun Ji ◽  
Yudong Wang
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Great Influence ◽  
Distribution Characteristics ◽  
Air Velocity ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Airflow Distribution ◽  
Slot Die ◽  
Center Area

AbstractTo investigate the distribution characteristics of the three-dimensional flow field under the slot die, an online measurement of the airflow velocity was performed using a hot wire anemometer. The experimental results show that the air-slot end faces have a great influence on the airflow distribution in its vicinity. Compared with the air velocity in the center area, the velocity below the slot end face is much lower. The distribution characteristics of the three-dimensional flow field under the slot die would cause the fibers at different positions to bear inconsistent air force. The air velocity of the spinning centerline is higher than that around it, which is more conducive to fiber diameter attenuation. The violent fluctuation of the instantaneous velocity of the airflow could easily cause the meltblowing fiber to whip in the area close to the die.

Into Mesh Lubrication of Spur Gears With Arbitrary Offset Oil Jet. Part 1: For Jet Velocity Less Than or Equal to Gear Velocity

1983 ◽  
Vol 105 (4) ◽  
pp. 713-718 ◽  
Author(s):  
L. S. Akin ◽  
D. P. Townsend
Keyword(s):  
Inclination Angle ◽  
Gear Tooth ◽  
Optimum Operating ◽  
Spur Gears ◽  
Optimum Operating Condition ◽  
Operating Condition ◽  
The Common ◽  
Jet Velocity ◽  
Oil Jet

An analysis was conducted for into mesh oil jet lubrication with an arbitrary offset and inclination angle from the pitch point for the case where the oil jet velocity is equal to or less than pitch line velocity. The analysis includes the case for the oil jet offset from the pitch point in the direction of the pinion and where the oil jet is inclined to intersect the common pitch point. Equations were developed for the minimum oil jet velocity required to impinge on the pinion or gear and the optimum oil jet velocity to obtain the maximum impingement depth. The optimum operating condition for best lubrication and cooling is provided when the oil jet velocity is equal to the gear pitch line velocity with both sides of the gear tooth cooled. When the jet velocity is reduced from pitch line velocity the drive side of the pinion and the unloaded side of the gear is cooled. When the jet velocity is much lower than the pitch line velocity the impingement depth is very small and may completely miss the pinion.

Electric Power Tower Inclination Angle Detection Method Based on SIFT Feature Matching

2012 ◽  
Vol 236-237 ◽  
pp. 759-764 ◽  
Author(s):  
Ping Yu ◽  
Bao Guo Dong ◽  
Yu Juan Xue
Keyword(s):  
Electric Power ◽  
Inclination Angle ◽  
Feature Matching ◽  
Feature Points ◽  
Simulation Test ◽  
Sift Feature ◽  
Material Resources ◽  
Maximum Angle ◽  
The Common ◽  
Routine Inspection

In video monitoring system of substation, in-process video inspection is used to detect abnormalities and provide corresponding solutions in a timely manner to avoid failures.As the common equipment，electric power tower’s inclination should be detected timely..It was hard to check the fault of tower inclination timely and accurately only by staff’s routine inspection,and it will spent much manpower and material resources by the manner of sensor. A manner of substation video inspection tower inclination angle detection based on SIFT feature matching and OTSU was presented in this paper. The tower inclination angle was calculated through the matched feature points. As is proved in the simulation test, this algorithm features simplicity and it can detect the maximum angle in all case of inclination .

scholarly journals A Discussion on the Effective Ventilation Distance in Dead-End Tunnels

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3352
Author(s):  
Manuel García-Díaz ◽  
Carlos Sierra ◽  
Celia Miguel-González ◽  
Bruno Pereiras
Keyword(s):  
Dead Zone ◽  
Air Velocity ◽  
Field Patterns ◽  
Working Face ◽  
Dead End ◽  
The Face ◽  
Airflow Field ◽  
Effective Ventilation ◽  
The Dead ◽  
Velocity Zone

Forcing ventilation is the most widely used system to remove noxious gases from a working face during tunnel construction. This system creates a region near the face (dead zone), in which ventilation takes place by natural diffusion, rather than being directly swept by the air current. Despite the extensive use of this system, there is still a lack of parametrical studies discerning the main parameters affecting its formation as well as a correlation indicating their interrelation. With this aim in mind, computational fluid dynamics (CFDs) models were used to define the dead zone based on the airflow field patterns. The formation of counter vortices, which although maintain the movement of air hinder its renewal, allowed us to discuss the old paradigm of defining the dead zone as a very low air velocity zone. Moreover, further simulations using a model of air mixed with NO2 offered an idea of NO2 concentrations over time and distance to the face, allowing us to derive at a more realistic equation for the effective distance. The results given here confirm the degree of conservativism of present-day regulations and may assist engineers to improve ventilation efficiency in tunnels by modifying the duct end-to-face distance.

scholarly journals Fiber Formation during Melt Blowing

2003 ◽  
Vol os-12 (2) ◽  
pp. 1558925003os-12 ◽  
Author(s):  
Randall R. Bresee ◽  
Wen-Chien Ko
Keyword(s):  
Fiber Diameter ◽  
Fiber Formation ◽  
Experimental Measurements ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Air Velocity ◽  
Melt Blowing ◽  
X Ray ◽  
X Ray Scattering ◽  
Insight Into

Experimental measurements are presented to provide phenomenological insight into the commercial melt blowing process. In particular, we discuss the following experimental measurements obtained at various die-collector locations: fiber diameter, fiber velocity, air velocity, fiber acceleration, fiber entanglement, fiber temperature, birefringence, wide-angle x-ray diffraction and small-angle x-ray scattering. Our discussion focuses on how these measurements provide insight into fiber formation during melt blowing.

A Lagrange Type Polymer Drawing Model of the Melt Blowing Nonwoven Process

2011 ◽  
Vol 148-149 ◽  
pp. 465-469 ◽  
Author(s):  
Hua Jun Chen ◽  
Ting Chen ◽  
Li Li Wu
Keyword(s):  
Experimental Data ◽  
Computer Simulations ◽  
High Velocity ◽  
Fiber Diameter ◽  
Air Velocity ◽  
Melt Blowing ◽  
Lagrange Method ◽  
Hot Air ◽  
Initial Polymer

Melt blowing process can produce superfine fibers. In this processs, the polymer is drawn by high velocity hot air. Lagrange method is empolyed to establish and solve the polymer drawing model. The fiber diameter and vibration are predicted with the model. The predicted fiber diameter concides with the experimental data. The fiber vibration becomes larger and larger with the increase of the die-to-collector distance. Computer simulations show that higher initial air velocity and higher initial polymer temperature can producefiner fibers while initial airtemperature contribute little to the polymer drawing.

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