scholarly journals Air velocity distribution of the circumferentially arranged nozzle group

2018 ◽  
Vol 22 (4) ◽  
pp. 1589-1593 ◽  
Author(s):  
Chen-Yang Xu ◽  
Li-Li Wu ◽  
Ting Chen
Keyword(s):  
Flow Field ◽  
Velocity Distribution ◽  
Air Flow ◽  
Hot Wire ◽  
Air Velocity ◽  
Centrifugal Spinning

The air-flow field of the circumferentially arranged nozzle group is modeled and simulated. The air velocity distribution is measured using a hot wire anemometer. The results show that the simulated velocities coincide with the measured ones, confirming the effectiveness of the model. Larger rotating speeds can yield larger air velocities, indicating that introducing auxiliary air is favorable to the polymer drawing in the centrifugal spinning.

Exploring the Polymer Drawing of the Air Centrifugal Spinning

2020 ◽  
Vol 13 (3) ◽  
pp. 189-195
Author(s):  
Jia-Jia Liu ◽  
Ting Chen ◽  
Li-Li Wu
Keyword(s):  
Flow Field ◽  
Nozzle Exit ◽  
Field Model ◽  
Rotation Speed ◽  
Air Flow ◽  
Radius Vector ◽  
Air Velocity ◽  
Centrifugal Spinning ◽  
Simulation Results

Background and Objective: The air-flow field of the air centrifugal spinning is simulated and measured. The simulated air velocities coincide well with the measured ones, confirming the correctness of the air-flow field model. Methods: The polymer drawing in the air-flow field of the air centrifugal spinning is modeled and simulated. Effects of the rotation speed and initial air velocity on the diameter and radius vector of the threadline are investigated. Results: The air velocity is found to decrease with the increase of the distance away from the nozzle exit. Simulation results show that both larger rotation speed and higher initial air velocity can reduce the threadline diameter. Conclusion: The radius vector of the threadline increases rapidly with the increase of the initial air velocity, which is helpful to reduce the threadline diameter.

Fiber spinning with airfields enhanced by airfoil louvers

2018 ◽  
Vol 89 (15) ◽  
pp. 3150-3158
Author(s):  
Kayla A Foley ◽  
Robert L Shambaugh
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Research Work ◽  
Fiber Spinning ◽  
Polymer Fiber ◽  
Air Flow Rate ◽  
Air Velocity ◽  
Melt Blowing ◽  
Slot Die ◽  
Spinning Process

Airfields are used in common polymer fiber spinning processes, such as melt blowing and spunbonding. A pair of louvers was installed in the air flow field of a melt blowing slot die. Previous research work has shown that, with louvers in place, the air velocity along the fiber threadline is higher than the velocity when louvers are not used. Since the air velocity is what drives the spinning process, the presence of louvers was expected to increase the attenuation of the molten filaments and thus improve the melt blowing process. Melt blowing runs were made with variable louver size (chord), louver separation, louver distance from the die face, the angle of the louvers relative to the die face, and air flow rate. Fibers were collected and fiber diameters were measured.

Experimental Investigation into a New Melt-Blowing Die for Dual Rectangular Jets

2014 ◽  
Vol 945-949 ◽  
pp. 270-273 ◽  
Author(s):  
Yu Dong Wang ◽  
Xin Hou Wang
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Air Flow ◽  
Hot Wire ◽  
Melt Blowing ◽  
Important Impact ◽  
Slot Die ◽  
Online Measurements ◽  
Turbulent Air Flow

In this work, online measurements of turbulent air flow field in the melt-blowing process for the slot die with inner stabilizing pieces and the corresponding blunt die were carried out with a hot-wire anemometer. The experiment results reveal that the inner stabilizing piece has an important impact on the flow field below the die face. The new modified die is aerodynamically superior, should contribute to produce much finer melt-blowing fibers and require less energy than the corresponding blunt die.

Investigation into the effect of the angle of dual slots on an air flow field in melt blowing via numerical simulation

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 337-342 ◽  
Author(s):  
Xin Sanfa ◽  
Wang Xinhou
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Boundary Conditions ◽  
Geometric Model ◽  
Air Flow ◽  
Air Velocity ◽  
Melt Blowing ◽  
Temperature Distributions ◽  
Velocity Pressure

AbstractThe effect of the angle of dual slots on an air flow field in melt blowing was researched via numerical simulation. Through establishing the geometric model of air flow field in melt blowing with dual slots, meshing, designating the boundary conditions and their parameters and numerical simulation, the result illustrates the influence of the angle of dual slots on the variations of air velocity, pressure and temperature distributions. Higher peak values of air velocity, pressure and temperature are obtained with larger angles of dual slots near the die, while only a few differences of these parameters are detected away from the die. Our results demonstrate the angle of 70° is the appropriate one that can produce the finest fibers.

scholarly journals Effects of the conduit geometry on the air flow field in the spunbonding process

2015 ◽  
Vol 19 (4) ◽  
pp. 1457-1458
Author(s):  
Li-Li Wu ◽  
Hong-Mei Sun ◽  
Ting Chen
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Air Flow ◽  
Air Velocity ◽  
Filament Diameter ◽  
Narrow Section

In the spunbonding process, the air flow field of the drawing conduit affects the polymer drawing and therefore the filament diameter greatly. Effects of the conduit parameters on the air flow field are studied using the previously established air flow field model. The results show that longer narrow section, longer contracting section and larger height of narrow entry are of benefit to increasing the air velocity, thus helpful for decreasing the filament diameter.

scholarly journals Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans

2018 ◽  
Vol 45 (2) ◽  
pp. 151-165 ◽  
Author(s):  
Milan Sekularac ◽  
Novica Jankovic
Keyword(s):  
Flow Field ◽  
Velocity Distribution ◽  
Road Traffic ◽  
Air Flow ◽  
Ventilation System ◽  
Traffic Load ◽  
Scaled Model ◽  
Numerical Work ◽  
Traffic Jam ◽  
Traffic Tunnel

To investigate air flow in longitudinally ventilated traffic tunnels, a scaled model of a typical road-traffic tunnel with an appropriate ventilation system based on axial ducted fans, is designed and built in the Lab. The focus of this paper is the airflow in a bi-directional traffic, two-lane tunnel. At the scale ratio of approx. 1:20, at 20.52m length it represents ? 400m of a realscale tunnel. The model consists of two parallel tunnel tubes, where the main tunnel (with a hydraulic diameter of ???1 ? 0.4m) has the geometry of a scaled road traffic-tunnel. The second tunnel (???2 ? 0.16m) has a smaller size and is circular in cross-section, used only to simulate airflow towards an evacuation tunnel tube. Thus the two tunnels are connected by the evacuation passages, equipped with adjustable escape doors. By a combination of experimental and numerical work, the air flow-field and the performance of the ventilation system are investigated. The velocity field and its turbulence properties exiting the fans were determined experimentally using hot-wire anemometry. These data were further processed to be used in the tunnel flow computations by CFD. The efficiency of momentum transfer (????, Kempf factor) of the longitudinal tunnel ventilation is determined. The effect that the imposed boundary conditions and the level of their detail, have within a CFD computation of tunnel airflow, with respect to accuracy, velocity distribution and computed ????. Finally a traffic-loaded (traffic ?jam?) case of flow is studied through experiment and CFD. The difficulty in assessing the required thrust of the plant in traffic-jam tunnel conditions is discussed, and the ventilation efficiency is estimated. Based on later results, the two limiting shapes of axial velocity distribution with respect to height above the road, in this type of tunnel and traffic, are estimated. The last result can be used as a realistic boundary condition (as inlet b.c. and/or initial condition) for numerical studies of flow and fire scenarios in such tunnels with the traffic load critical for design.

scholarly journals Effect of Airflow Field in the Tangential-Longitudinal Flow Threshing and Cleaning System on Harvesting Performance

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Taibai Xu ◽  
Yaoming Li
Keyword(s):  
Flow Field ◽  
Working Conditions ◽  
Air Flow ◽  
Internal Space ◽  
Air Velocity ◽  
Rotating Speed ◽  
Cleaning System ◽  
Cleaning Device ◽  
Combine Harvester ◽  
Working Parameters

The threshing and cleaning device in the grain combine harvester is located in the same airtight space, and the air flow field in it should also be studied and tested as a whole system. In order to study the distribution of air flow field and the influence of working parameters on the air flow field in the internal space of threshing and cleaning system, the method of predicting harvest performance indexes (grain loss rate and grain impurity rate) by air flow field analysis was explored. First of all, taking the longitudinal grain combine harvester of our research group as the test object and taking the rotating speed of centrifugal fan, the angle of fan plate, the opening of chaffer, and the rotating speed of threshing cylinder as the research factors, the internal space flow channel model of threshing and cleaning system under different working conditions was established and CFD software was used to simulate and analyze the air flow field. At the same time, the hot wire anemometer is used to measure and verify the distribution of air flow field in the threshing and cleaning system under various working conditions. Then, the harvest performance index of the threshing and cleaning system under the rated feeding rate is tested under the corresponding working conditions to find the relationship between the distribution of air flow field and harvest performance, put forward the corresponding analysis and prediction methods, and establish the mathematical relationship model between the simulated air flow field and harvest performance index. The results of simulation and experiment show that the average air velocity can more accurately reflect the cleaning performance. The mathematical function of the relation curve is Y = 11.71X − 4.76, and the prediction error is within 9.4%. The air velocity in the middle area of the vibrating screen is approximately in proportion to the cleaning performance, which provides the theoretical and experimental basis for the design of the threshing and cleaning device and the adjustment of the working parameters in the field harvest. In addition, it can save the design time and cost and reduce the seasonal impact of field experiment.

The Effect of Orifice Plate on Flow Field and Thermal Environment in Oven Box

2015 ◽  
Vol 713-715 ◽  
pp. 47-50
Author(s):  
Hao Li ◽  
Zhi Jun Zou ◽  
Fei Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Thermal Environment ◽  
Air Flow ◽  
Orifice Plate ◽  
Air Velocity ◽  
Change Rate ◽  
Air Volume

Air velocity in oven box is an important factor. The value of air velocity will affect the result of drying. This paper use the method of numerical simulation to research the effect of orifice plate on flow field and thermal environment in oven box. The results show the change rate of thermal environment & air flow field in oven box is depend on supply air volume, and the use of orifice plate will affect the flow field obviously.

scholarly journals Numerical simulation of the air flow field in the foreign fiber separator

2016 ◽  
Vol 20 (3) ◽  
pp. 953-956 ◽  
Author(s):  
Ting Chen ◽  
Kang Yang ◽  
Li-Li Wu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Turbulence Intensity ◽  
Theoretical Basis ◽  
Air Flow ◽  
Nozzle Diameter ◽  
Design Parameters ◽  
Air Velocity ◽  
Nozzle Axis

The air flow field of a foreign fiber separator is simulated numerically. Effects of design parameters such as the nozzle diameter and entrance width of the noil box on the air velocity along nozzle axis, turbulence intensity, and jet deflection distance are studied. Larger nozzle diameters and larger entrance widths of the noil box are advantageous to the elimination of foreign fibers. The results provide a theoretical basis for the design of foreign fiber separators.

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.

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