Effect of slot end faces on the three-dimensional airflow field from the melt-blowing die

2020 ◽  
Vol 40 (7) ◽  
pp. 607-613
Author(s):  
Yudong Wang ◽  
Jianping Zhou
Keyword(s):  
Numerical Calculation ◽  
Flow Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Central Area ◽  
Computational Domain ◽  
Melt Blowing ◽  
Slot Die ◽  
Calculation Results ◽  
Airflow Field

AbstractIn order to investigate the effect of the slot ends of the melt-blowing die on the three-dimensional airflow field distribution and the fiber draft, the numerical calculation was carried out. The computational domain of the slot die was established with Gambit, and the flow field was calculated using FLUENT. Compared with the experimental data collected by a hot-wire anemometer, the numerical calculation results are credible. The results show that the slot end face has a certain influence on the three-dimensional flow field distribution under the melt-blowing die. The air velocity and temperature in the center region are quite different from those near the slot-end face. As the distance from the center of the flow field increases, the velocity and temperature on the spinning line begin to decrease. The velocity and temperature distributions of the spinning lines in the central area and nearby areas are almost the same; the temperature and velocity values on the spinning lines near the slot end are the lowest. The distribution characteristics of the three-dimensional airflow field could affect the uniformity of the fiber diameter and the meltblowing products.

Numerical Simulation of Viscous Flow-Field in Cascade Using Thin-Layer Equations and AF Method

1999 ◽  
Author(s):  
Yumin Xiao ◽  
R. S. Amano
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
Viscous Flow ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Factorization Method ◽  
Computational Domain ◽  
Approximate Factorization ◽  
Calculation Results ◽  
Transonic Cascade

Abstract In this paper an implicit 3-D solver for computations of a viscous flow has been developed and the computations of the flow between blade passage are presented. This method employs an AF (Approximate Factorization) method in which four techniques are incorporated to speed up convergence to the steady-state solutions: (1) body-fitted H-grid; (2) artificial viscosity; (3) implicit residual smoothing; and (4) local time-stepping. The two-dimensional pseudo-characteristic method was used to determine the inlet and outlet boundary conditions of the computational domain and the periodic boundary conditions were used at inter-boards. The validation cases include subsonic and transonic viscous flows in C3X cascade. Results for these turbine cascade flows are presented and compared with experiments at corresponding conditions. Computed pressure distributions on blade surfaces show good agreement with the published experimental data. This method was further applied to a three-dimensional case and demonstrated the code capability for predicting the secondary flow in a 3-D transonic flow-field. From these computations it was found that the proposed method possesses superior convergence characteristics and can be extended to unsteady flow calculations. Finally, it was observed that the three-dimensional calculation results show that the secondary flow mechanism in a transonic cascade seems to be quit different from those, in a subsonic case.

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.

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.

scholarly journals Optimal design for the dual slot die in melt blowing process

2014 ◽  
Vol 18 (5) ◽  
pp. 1714-1715
Author(s):  
Li-Li Wu ◽  
Ting-Ting Cheng ◽  
Chuan Xu ◽  
Ting Chen
Keyword(s):  
Experimental Design ◽  
Optimal Design ◽  
Flow Field ◽  
Design Method ◽  
Air Flow ◽  
Variance Analysis ◽  
Orthogonal Experimental Design ◽  
Melt Blowing ◽  
Experimental Design Method ◽  
Slot Die

The parameters of the dual slot die in an industrial melt blowing equipment are designed optimally using the orthogonal experimental design method. The air flow fields of different die parameters are simulated. Effects of the die parameters are analyzed using variance analysis. The results show that the inset distance and slot width have significant effects on the air flow field while effect of the slot angle is unremarkable.

Numerical Simulation of Partial Cavitating Flow of 2-D Hydrofoil in Viscous Flow

2012 ◽  
Vol 214 ◽  
pp. 102-107
Author(s):  
Xiao Hui He ◽  
Lei Gao ◽  
Hong Bing Liu ◽  
Zhi Gang Li
Keyword(s):  
Numerical Simulation ◽  
Numerical Calculation ◽  
Flow Field ◽  
Viscous Flow ◽  
Reynolds Equation ◽  
Cavitating Flow ◽  
Partial Cavitation ◽  
Calculation Results ◽  
Control Equation ◽  
Precise Degree

This paper has studied the partial cavitation of 2-D hydrofoil based on the theory of viscous flow. The numerical calculation sets forth from the complete N-S equation and adopts the two-equation turbulence model closed Reynolds equation. As the basic control equation, the cavitating flow adopts the Rayleigh plesset model and calculates the zero angle of attack. At the same time, it calculates the influences of different ship speeds on the hydrofoil partial cavitating flow and analyzes the flow field of the hydrofoil. In addition, it makes comparisons on the calculation results and the published test conclusions. The results have shown that the calculation method in this paper has relatively good calculation precise degree.

Time Accurate Euler Simulation of Interaction of Nozzle Wake and Secondary Flow With Rotor Blade in an Axial Turbine Stage Using Nonreflecting Boundary Conditions

1995 ◽  
Author(s):  
S. Fan ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
Unsteady Flow ◽  
Secondary Flow ◽  
Rotor Blade ◽  
Three Dimensional ◽  
Computational Domain ◽  
Turbine Stage ◽  
Axial Turbine ◽  
Unsteady Pressure

The objective of this paper is to investigate the three dimensional unsteady flow interactions in a turbomachine stage. A three-dimensional time accurate Euler code has been developed using an explicit four-stage Runge-Kutta scheme. Three-dimensional unsteady non-reflecting boundary conditions are formulated at the inlet and at the outlet of the computational domain to remove the spurious numerical reflections. The three-dimensional code is first validated for 2-D and 3-D cascades with harmonic vortical inlet distortions. The effectiveness of non reflecting boundary conditions is demonstrated. The unsteady Euler solver is then used to simulate the propagation of nozzle wake and secondary flow through rotor and the resulting unsteady pressure field in an axial turbine stage. The three dimensional and time dependent propagation of nozzle wakes in the rotor blade row and the effects of nozzle secondary flow on the rotor unsteady surface pressure and passage flow field are studied. It was found that the unsteady flow field in the rotor is highly three-dimensional and the nozzle secondary flow has significant contribution to the unsteady pressure on the blade surfaces. Even though the steady flow at the midspan is nearly two-dimensional, the unsteady flow is 3-D and the unsteady pressure distribution can not by predicted by a 2-D analysis.

Numerical Simulation of Flow Process of Ammonium Persulfate Crystallizer

2014 ◽  
Vol 997 ◽  
pp. 396-400
Author(s):  
Yu Guang Fan ◽  
Ting Wei
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Ammonium Persulfate ◽  
Flow Process ◽  
Calculation Results ◽  
Crystallization Effect ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
Selection Of

The method of computational fluid dynamics (CFD) is used to three-dimensional numerical simulation for the fluid flow process of ammonium persulfate crystallizer. By using standard model, this paper respectively simulated the flow field within the crystallizer in the impeller installation height of 1.2 m while stirring speed is of 60 r/min, 100 r/min and 200 r/min; and simulated the impact of the flow field inside the crystallizer when the stirring speed of 100 r/min and impeller installation height respectively is of 0.7 m, 1.2 m and 1.7 m. That calculation results show that: the velocity gradient is mainly concentrated in the area of internal draft tube and paddle around. With the increase of impeller speed, the flow velocity of the fluid within the crystallizer corresponding increases; and the energy also gradually decreases from mixing impeller to the settlement zone with the loss of the installation height, and the kinetic energy in the bottom of the crystallizer is reduced. Considering the energy and crystallization effect, selection of mixing speed of 100 r/min or so and installation height of about 1.2 m is more appropriate.

scholarly journals Three-Dimensional Numerical Modeling and Roof Deformation Analysis of Yuanjue Cave Based on Point Cloud Data

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhigang Meng ◽  
Manchao He ◽  
Zhigang Tao ◽  
Bin Li ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Rock Mass ◽  
Numerical Calculation ◽  
Point Cloud ◽  
Three Dimensional ◽  
Calculation Model ◽  
Deformation Analysis ◽  
Cloud Data ◽  
Heritage Site ◽  
Calculation Results ◽  
Multifactor Coupling

Yuanjue Cave is the core exquisite cultural relic of the Dazu Stone Carvings World Cultural Heritage Site. For hundreds of years, with the continuous effect of natural forces and the erosion of various deterioration factors, the sidewall and roof rock mass of Yuanjue Cave were eroded, some parts of supporting rock mass were fragmented, and the boundary conditions of the rock mass have deteriorated, which have seriously endangered the Yuanjue Cave; once the roof collapses, the national treasure in the cave will be destroyed. In order to preevaluate the stability characteristics of the Yuanjue Cave rock mass and provide key parameters for the preventive protection of the Yuanjue Cave, this paper firstly established a refined database of key parameters of Yuanjue Cave and adjacent areas (geometry, geology, physical properties) based on three-dimensional laser point cloud scanning, a fine survey of adjacent areas, engineering geophysical prospecting, and indoor multifactor coupling tests. Then, based on FLAC3D finite difference numerical simulation technology, an accurate three-dimensional numerical calculation model of Yuanjue Cave was constructed. Finally, the model was used to analyze the roof stability of Yuanjue Cavern, revealing the deformation laws of the Yuanjue Cave roof under static load conditions, and the numerical calculation results were compared with the on-site measured results, verifying the feasibility of the high-precision modeling method, and the reliability of the numerical calculation results provided a reference for the preventive protection of the cultural relics of the cave temple.

Research on Temperature Rise of Wet Clutch Based on Multi-Field Coupling

2019 ◽  
Author(s):  
Bangzhi Wu ◽  
Datong Qin ◽  
Jianjun Hu ◽  
Qing Zhang
Keyword(s):  
Temperature Field ◽  
Numerical Calculation ◽  
Flow Field ◽  
Field Distribution ◽  
Working Conditions ◽  
Temperature Rise ◽  
Automatic Transmission ◽  
Calculation Model ◽  
Field Coupling ◽  
Wet Clutch

Abstract Wet clutch is widely used in vehicle power transmission, especially in dual clutch automatic transmission. However, due to the unclear understanding of clutch temperature distribution and its influencing factors, the clutch is prone to excessive temperature rise or even wear under severe working conditions or continuous starting conditions. In this paper, the finite element model of stress field distribution of friction pair is established by considering the non-uniform fixed constraint of clamping spring and the non-uniform contact of hydraulic cylinder. Based on the inclined groove structure of the friction plate, the numerical calculation model of the flow field in the groove is established by the finite volume method. On this basis, considering the time-varying characteristics of stress distribution and cooling flow field distribution of clutch friction pairs, a numerical calculation model of clutch temperature field is established, and a multi-field coupling calculation method of clutch is proposed. The distribution of temperature field under different working conditions during clutch engagement is obtained by numerical calculation. The results show that the temperature rise of clutch depends on the target speed of the clutch driving end and the load on the driven end. The research results can provide guidance for the design and control of the clutch.

The Numerical Simulation of the Flow Field in the Underground Hydrocyclone

2013 ◽  
Vol 655-657 ◽  
pp. 470-475
Author(s):  
Jing Chang Wang ◽  
Fu Lai Guo ◽  
Meng Hua Wu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Field Distribution ◽  
Phase Distribution ◽  
Three Dimensional ◽  
Internal Flow ◽  
No Formation ◽  
The Media ◽  
Solid Liquid ◽  
Air Column

For preventing sand in underground oil, this paper structures a model of hydrocyclone with the inside cyclone and the outside one seriesing and describes how it works. By the TGrid procedures, the all of the hydrocyclone is meshed with the tetrahedral and the boundary conditions are determined. The methods of Three-dimensional numerical simulation in FLUENT are used to simulate the velocity field distribution, the pressure field distribution, the path lines of the separated medition characteristics of the separated medium and the phase distribution of the medium. The affect of the internal separated medition characteristics to the separated performance is analysed. Through the simulation, it is found that the spiral fin in the hydrocyclone can guide the fluid to produce a vortex flow to meet the purpose of separating the solid-liquid. There is no formation of the air column comparing with the conventional cyclone, so the internal flow field is more stable to conductive to the separation of the media. It provides a basis for the improvement of the cyclone.

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