scholarly journals Dynamic simulation of fiber orientation in the gap flow field between two rotating cylinders

2015 ◽  
Vol 64 (11) ◽  
pp. 118102
Author(s):  
Yang Bin-Xin ◽  
Ouyang Jie ◽  
Zhou Wen ◽  
Wang Fang ◽  
Li Xue-Juan
Keyword(s):  
Flow Field ◽  
Dynamic Simulation ◽  
Fiber Orientation ◽  
Rotating Cylinders ◽  
Gap Flow

Dynamic Simulation of Fusion Process and Analysis of Flow Field

2008 ◽  
Vol 28 (9) ◽  
pp. 1049-1058 ◽  
Author(s):  
Supei Zheng ◽  
Jie Ouyang ◽  
Ling Zhang ◽  
Hongping Zhang
Keyword(s):  
Flow Field ◽  
Dynamic Simulation ◽  
Fusion Process

Simulation and Experiment Research on Liquid Channel of Diffuser Blade by Electrochemical Machining

2021 ◽  
Author(s):  
Jinkai Xu ◽  
Jin Tao ◽  
Wanfei Ren ◽  
Kun Tian ◽  
Xiaoqing Sun ◽  
...  
Keyword(s):  
Flow Field ◽  
Electrochemical Machining ◽  
Leading Edge ◽  
Feed Speed ◽  
Trailing Edge ◽  
Gap Flow ◽  
Clearance Flow ◽  
Field Uniformity ◽  
Simulation And Experiment ◽  
Channel Center

Abstract Aiming to solve the problems of the low electrolyte flow rate at leading edge and trailing edge and poor uniformity of the end clearance flow field during the electrochemical machining (ECM) of diffuser blades, a gap flow field simulation model was established by designing three liquid-increasing channels at the leading edge and the trailing edge of the cathode. The simulation results indicate that the liquid-increasing hole channel (LIHC) with an outlet area S of 1.5 mm2 and a distance L from channel center to edge point of 3.2 mm achieves optimal performance. In addition, the experiment results show that the optimized cathode with liquid-increasing hole channel (LIHC) significantly improves the machining efficiency, accuracy and surface quality. Specifically, the feed speed increased from 0.25 mm/min to 0.43 mm/min, the taper decreased from 4.02° to 2.45°, the surface roughness value of blade back reduced from 1.146 µm to 0.802 µm. Moreoever, the roughness of blade basin decreased from 0.961 µm to 0.708 µm, and the roughness of hub reduced from 0.179 µm to 0.119 µm. The results prove the effectiveness of the proposed method, and can be used for ECM of other complex structures with poor flow field uniformity.

Simulation of Gap Flow Field in EDM Process Uesd Oil-in-Water Working Fluid

2020 ◽  
Vol 841 ◽  
pp. 232-237
Author(s):  
Wei Jie Chang ◽  
Yan Ying Xi ◽  
Hao Wei Li
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Corrosion Products ◽  
Working Fluid ◽  
Electrical Discharges ◽  
Electric Discharge Machining ◽  
Processing Depth ◽  
Gap Flow ◽  
Oil In Water ◽  
Edm Process

Electric Discharge Machining (EDM) working fluid as a medium can control electrical discharges occur, carry away the heat, compress discharge channel and help remove the corrosion products out of the gap. The main working fluids used in EDM are oil-based working fluid, gas-based working fluid, powder mixed working fluid, gas mixed working fluid and water-based working fluid. In order to improve the green and safety of EDM working fluid, an oil-in-water working fluid is proposed. A gap flow field model of EDM is established by using external flushing fluid. The flow field distribution, pressure distribution and corrosion products distribution of the machining gap are analyzed by using computational fluid dynamics. The effects of inlet pressure, processing depth and electrode size on the flow field are studied. The simulated results show that within a certain range, removal effect of the corrosion products will increase with inlet velocity and the size of electrode and decrease with processing depth.

A method for dynamic simulation of rigid and flexible fibers in a flow field

1993 ◽  
Vol 98 (1) ◽  
pp. 644-650 ◽  
Author(s):  
Satoru Yamamoto ◽  
Takaaki Matsuoka
Keyword(s):  
Flow Field ◽  
Dynamic Simulation ◽  
Flexible Fibers

Computational Fluid Dynamics Analysis of Working Fluid Flow and Machining Debris Movement in End Electrical Discharge Milling and Mechanical Grinding Compound Machining

2012 ◽  
Vol 621 ◽  
pp. 191-195 ◽  
Author(s):  
Ren Jie Ji ◽  
Yong Hong Liu ◽  
Chao Zheng ◽  
Fei Wang ◽  
Yan Zhen Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Electrical Discharge ◽  
Great Influence ◽  
Working Fluid ◽  
Tool Electrode ◽  
Process Performance ◽  
Mechanical Grinding ◽  
Gap Flow ◽  
Computational Fluid Dynamics Analysis

The working fluid flow and the machining debris movement in the machining gap exercise a great influence on the process performance in end electrical discharge milling and mechanical grinding compound machining. In this paper, the working fluid flow and the machining debris movement in the machining gap are modeled based on the liquid-solid two-phase flow theory. The gap flow field is calculated with the software of Fluent, and the velocity field and the pressure field are analyzed. The results show that in the gap flow field of the compound machining, the working fluid flow can be accelerated, and the machining debris can be ejected timely by the rapid rotation of the tool electrode, so the compound process performance can be enhanced.

Turbulence and Fiber Orientation in the Converging Section of a Paper-Machine Headbox

2002 ◽  
Author(s):  
Suqin Dong ◽  
Xiaosi Feng ◽  
Martha Salcudean ◽  
Ian Gartshore ◽  
Mohammad Shariati
Keyword(s):  
Flow Field ◽  
Fiber Orientation ◽  
Wire Mesh ◽  
Circulation Rate ◽  
Paper Machine ◽  
Pulp Fibers ◽  
Mean Flow ◽  
Mean Velocity ◽  
The Mean ◽  
Paper Machine Headbox

The rapidly converging section of a paper-machine headbox carries a dilute concentration of pulp fibers to the wire mesh where the fibers are dried to become paper. Ideally, the mean velocity distribution in the fluid mixture leaving the converging section (or slice as it is called) should be uniform over the paper thickness direction and across the entire span of the slice exit. Non-uniformities in this distribution can result in defects in the paper being produced by the machine. A complete computer simulation of a typical headbox, reported here, identifies two important sources of mean velocity defects as the re-circulation rate and the design shape of the manifold, which initially spreads the pulp into the several hundreds of tubes which deliver it, in turn, to the converging section. As emphasized in the present report, it is critically necessary for the proper identification of defects, that there be a single simulation of the complete headbox, correctly locating individual tubes and other major components. The turbulence which occurs in the converging section does not affect the mean flow distribution significantly but it is critically important in preventing unwanted fiber flocculation and in providing a degree of dispersion for the fibers, which would otherwise be strongly oriented in the flow direction under the action of the mean rate-of-strain field created by the rapid convergence. A detailed knowledge of this turbulence is therefore essential in order to model the fiber motion and the effectiveness of the paper-machine, and to predict the quality of the paper produced. LDA measurements of the three turbulence components have been made in a laboratory scale paper-machine converging section, and corresponding measurements have also been made of the statistical orientation of short pieces of nylon thread, representing pulp fibers, carried by the flow. CFD simulations of this rapidly converging flow are reported here. Results using the usual k-ε and Reynolds stress turbulence models are compared to the appropriate experimental measurements, and found to be inaccurate. A large eddy simulation (LES) computation of the converging section is next reported. The calculated time-averaged turbulence components are compared to the measured values along the centerline of the converging section. Qualitatively, the calculated and observed turbulence distributions follow similar trends. Differences occur because of the significantly different initial conditions for the measured and calculated cases. A Lagrangian tracking scheme capable of simulating the motion of flexible or rigid individual fibers in a computed flow field has been devised and is used in the LES representation of turbulence (and other simpler flow field representations) in the convergence to predict the statistical orientation of nylon “fibers”. Two different schemes to couple the LES flow field calculations with the fiber model are reported, one using a fixed or “frozen” 3D flow field from the LES calculations and the other using the complete unsteady LES flow field. Both these give similar (but not identical) statistical results for the fiber orientation. This suggests that the much simpler “frozen field” technique can be used in future computations, making the numerical prediction of statistical fiber orientations in a diffuser (or other complex geometries) practical with the realistic LES scheme and present computational resources.

scholarly journals Effects of Simulated Rotation on Tip Leakage in a Planar Cascade of Turbine Blades: Part I — Tip Gap Flow

1991 ◽  
Author(s):  
M. I. Yaras ◽  
S. A. Sjolander
Keyword(s):  
Flow Field ◽  
Relative Motion ◽  
Wall Motion ◽  
Turbine Blades ◽  
Pressure Probe ◽  
Tip Leakage ◽  
Gap Flow ◽  
Axial Turbines ◽  
Downstream Flow ◽  
Tip Gap Flow

The paper presents further results from a continuing study on tip leakage in axial turbines. Rotation has been simulated in a linear cascade test section by using a moving-belt tip wall. Measurements were made inside the tip gap with a three-hole pressure probe for a clearance size of 3.8 percent of the blade chord. Two wall speeds are considered and the results are compared with the case of no rotation. As in other experiments, significant reduction in the gap mass flow rate is observed due to the relative motion. The detailed nature of the measurements allows the dominant physical mechanism by which wall motion affects the tip gap flow to be identified. Based on the experimental observations, an earlier model for predicting the tip gap flow field is extended to the case of relative wall motion. Part II of the paper examines the effect of the relative motion on the downstream flow field and the blade loading.

Measuring Fiber Orientation in Nonwovens Part IV: Flow Field Analysis

1997 ◽  
Vol 67 (3) ◽  
pp. 181-187 ◽  
Author(s):  
B. Pourdeyhimi ◽  
R. Dent
Keyword(s):  
Image Analysis ◽  
Flow Field ◽  
Fiber Orientation ◽  
Field Analysis ◽  
Local Orientation ◽  
Image Analysis Technique ◽  
Fourier Methods ◽  
Analysis Technique ◽  
Flow Field Analysis ◽  
Simulated Images

This paper addresses the development of the image analysis technique of flow field analysis to evaluate local orientation in a fibrous assembly. The algorithms are evaluated using simulated images presented in Part I of the series. The results are compared with those from the tracking and Fourier methods presented in Parts II and III.

Research on the Initial Disturbance of Vehicular Missile with System Vibration Analysis

2012 ◽  
Vol 625 ◽  
pp. 134-139 ◽  
Author(s):  
Chong Zhang ◽  
Yi Jiang
Keyword(s):  
Flow Field ◽  
Dynamic Simulation ◽  
Vibration Analysis ◽  
Jet Flow ◽  
Initial Disturbance ◽  
Flexible Coupling ◽  
Study Results ◽  
System Vibration ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

This paper is based on the complex multiple vehicular missile launch simulation model, researches the influence of combustion jet flow to the initial disturbance of missile. It establishes rigid-flexible coupling dynamic model by use of Adams and Ansys, and calculates the value of combustion jet flow field in missile box by means of Fluent. The rigid-flexible coupling dynamic simulation for the whole launch process is carried out. The study results show that the simulation with loading jet flow can accurately tend to real launch environment, it has great significance to optimize the simulation and to improve the accuracy of the simulation.

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