CFD Simulation of Dielectric Fluid Flow in Micro Electro Discharge Milling Process

2018 ◽  
Vol 5 (11) ◽  
pp. 24792-24798
Author(s):  
S.A. Mullya ◽  
G. Karthikeyan
Keyword(s):  
Fluid Flow ◽  
Cfd Simulation ◽  
Milling Process ◽  
Dielectric Fluid

scholarly journals High-Efficient Micro Reacting Pipe with 3D Internal Structure: Design, Flow Simulation, and Metal Additive Manufacturing

2020 ◽  
Vol 10 (11) ◽  
pp. 3779
Author(s):  
Xiaomin Chen ◽  
Di Wang ◽  
Jingming Mai ◽  
Xiaojun Chen ◽  
Wenhao Dou
Keyword(s):  
Fluid Flow ◽  
Additive Manufacturing ◽  
Internal Structure ◽  
Cfd Simulation ◽  
Structure Design ◽  
Design Flow ◽  
Mixing Efficiency ◽  
Metal Additive Manufacturing ◽  
High Efficient ◽  
Metal Additive

The micro reacting pipe with 3D internal structure, which is a micromixer with the shape of the pipe, has shown great advantages regarding mass transfer and heat transfer. Since the fluid flow is mostly laminar at the micro-scale, which is unfavorable to the diffusion of reactants, it is important to understand the influence of the geometry of the microchannel on the fluid flow for improving the diffusion of the reactants and mixing efficiency. On the other hand, it is a convenient method to manufacture a micro reacting pipe in one piece through metal additive manufacturing without many post-processing processes. In this paper, a basis for the design of a micromixer model was provided by combining the metal additive manufacturing process constraints with computational fluid dynamics (CFD) simulation. The effects of microchannel structures on fluid flow and mixing efficiency were studied by CFD simulation whose results showed that the internal micro-structure had a significantly positive effect on the mixing efficiency. Based on the simulation results, the splitting-collision mechanism was discussed, and several design rules were obtained. Two different materials were selected for manufacturing with the laser powder bed fusion (L-PBF) technology. After applying pressure tests to evaluate the quality of the formed parts and comparing the corrosion-resistance of the two materials, one material was picked out for the industrial application. Additionally, the chemical experiment was conducted to evaluate the accuracy of the simulation. The experimental results showed that the mixing efficiency of the micro reacting pipe increased by 56.6%, and the optimal determining size of the micro reacting pipe was 0.2 mm. The study can be widely used in the design and manufacture of a micromixer, which can improve efficiency and reacting stability in this field.

Control of Dielectric Fluid Flow Distribution in Micro-Tubes With EHD Conduction Pumping: Numerical Study

2011 ◽  
Author(s):  
Miad Yazdani ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Fluid Flow ◽  
Electric Field ◽  
Conduction Mechanism ◽  
Numerical Study ◽  
Fluid Motion ◽  
Flow Distribution ◽  
Operating Conditions ◽  
Dielectric Fluid ◽  
Total Flow ◽  
Flow Through

The control of fluid flow distribution in micro-scale tubes is numerically investigated. The flow distribution control is achieved via electric conduction mechanism. In electrohydrodynamic (EHD) conduction pumping, when an electric field is applied to a fluid, dissociation and recombination of electrolytic species produces heterocharge layers in the vicinity of electrodes. Attraction between electrodes and heterocharge layers induces a fluid motion and a net flow is generated if the electrodes are asymmetric. The numerical domain comprises a 2-D manifold attached to two bifurcated tubes with one of the tubes equipped with a bank of uniquely designed EHD-conduction electrodes. In the absence of electric field, the total flow supplied at the manifold’s inlet is equally distributed among the tubes. The EHD-conduction, however, operates as a mechanism to manipulate the flow distribution to allow the flow through one branch surpasses the counterpart of the other branch. Its performance is evaluated under various operating conditions.

Numerical Simulation of Fluid Flow and Heat Transfer Under Flow Fluctuation Condition in Horizontal Tube

2010 ◽  
Author(s):  
Yusheng Liu ◽  
Puzhen Gao ◽  
Dianchuan Xing
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Nuclear Power ◽  
Cfd Simulation ◽  
Horizontal Tube ◽  
Heat Fluxes ◽  
Practical Significance ◽  
Flow And Heat Transfer ◽  
Flow Fluctuation ◽  
Computational Fluid Dynamics Cfd

Fluctuating flow is widely presented in nuclear power plant operating procedure. When the fluctuating flow occurs in the loop, the fluid flow and heat transfer in the core will be affected, which makes the study of flow fluctuation have more practical significance. With computational fluid dynamics (CFD), characteristics of fluid flow and heat transfer are numerically simulated in a horizontal tube under periodical fluctuating flow. The influences of different factors on the fluid flow and heat transfer are analyzed. The simulation results of steady flow and heat transfer in horizontal tube agree with the traditional empirical correlations’ results, which validates the feasibility of doing this research using CFD simulation. The horizontal tube fluctuation flow and heat transfer with different flow fluctuation periods, fluctuation relative amplitudes and heat fluxes are numerically simulated. The results show that the smaller the flow fluctuation period is, the larger the flow fluctuation relative amplitude we get, and the more evident influence of flow fluctuation on fluid flow and heat transfer can be found. The larger the heat flux is, the larger amplitude of temperature fluctuation of fluid will be. What is more, there is a lag in phase between friction coefficient and velocity, which is not presented between heat transfer coefficient and velocity.

On the mechanism of glow of a high-speed dielectric-fluid flow in a narrow dielectric channel

2006 ◽  
Vol 51 (2) ◽  
pp. 86-89 ◽  
Author(s):  
D. S. Baranov ◽  
N. S. Bukharin ◽  
S. Ya. Gertsenshteĭn ◽  
A. A. Monakhov
Keyword(s):  
Fluid Flow ◽  
High Speed ◽  
Dielectric Fluid

CFD Based Investigations into Optimization of Diffuser Angle on Rear Bus Body

2016 ◽  
Vol 836 ◽  
pp. 127-131 ◽  
Author(s):  
Wawan Aries Widodo ◽  
Mutiara Nuril Karohmah
Keyword(s):  
Fluid Flow ◽  
Lift Force ◽  
Bluff Body ◽  
Cfd Simulation ◽  
Aerodynamic Forces ◽  
Wake Structure ◽  
Bus Body ◽  
Simulation Results ◽  
Drag And Lift ◽  
Diffuser Angle

Fluid flow interaction around bluff body to create aerodynamic forces including drag and lift force. The strategy to improve arodynamic forces to modify the shape of rear body. This investigation is conducted to simulate fluid flow past a bus body with variation of diffuser angle on the rear. The diffuser angle was set to 0°, 6°, 12°, and 18°, respectively. The CFD simulation results shown that diffuser on rear body bus models able to improve the aerodynamic forces and wake structure are correspond with incresing diffuser angle. The drag coefficient was reduced until 2.3% is related with diffuser angle (β) 180, also, diffuser angle (β) 120 capable to increase downforce significantly until ten times are compared with zero diffuser angle.

Leakages Through Radial Cracks in Cement Sheaths: Effect of Geometry, Viscosity and Aperture

2020 ◽  
Author(s):  
Ragnhild Skorpa ◽  
Torbjørn Vrålstad
Keyword(s):  
Fluid Flow ◽  
Cfd Simulation ◽  
Mechanical Damage ◽  
Simulation Software ◽  
Methane Gas ◽  
Flow Through ◽  
Cement Sheath ◽  
Well Abandonment ◽  
3D Volume ◽  
Radial Cracks

Abstract Annular cement sheath is considered to be one of the most important barrier elements in the well, both during production and after well abandonment. It is however well-known that mechanical damage to the cement sheath might result in leakage pathways, such as microannuli and radial cracks, and thus loss of zonal isolation. In this paper we have studied the effect of geometry, aperture and viscosity on the resulting pressure driven flow through real radial cracks in cement sheaths using Computational Fluid Dynamics (CFD) simulations. Real radial cracks were created by downscaled laboratory pressure cycling experiments and the resulting geometries were mapped by X-ray Computed Tomography (CT). This gave a unique 3D volume of the degraded cement sheaths which provides detailed information about the morphology, such as the irregular apertures and roughness, as well as locations of the radial cracks. In this study, we have used five experimentally created geometries, varying from barely connected to fully connected and almost uniform cracks. Additionally, theoretical uniform models with homogeneous aperture and a smooth surface were created for comparison. The simulations were performed by importing the experimentally created leak paths into a CFD simulation software, making it possible to determine the actual flowrate as a function of pressure drop. Methane gas, water and oil was used as model fluids. The simulation results show that fluid flow through real cracks in cement sheath is complex with torturous paths, especially around bottlenecks and narrow sections. Additionally, the results show that flow of both methane gas- and water are not linear and hence does not follow Darcy’s law. This illustrates that simple models are not able to fully describe fluid flow through such complex geometries.

CFD Simulation on Flow Distribution in Plate-Fin Heat Exchangers

2013 ◽  
Vol 655-657 ◽  
pp. 445-448
Author(s):  
Zhe Zhang ◽  
Jin Jin Tian ◽  
Yong Gang Guo
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Perforated Plate ◽  
Flow Distribution ◽  
Numerical Results ◽  
Flow Maldistribution ◽  
The Mathematical Model ◽  
First Time ◽  
Flow Nonuniformity

The influences of the conventional header configuration used in industry at present on the fluid flow distribution in plate-fin heat exchanger were numerically investigated. The numerical results showed that the fluid flow maldistribution is very serious in the heat exchanger. The header configuration with perforated plate was brought forward for the first time. The computational results indicated that the improved header configuration can effectively improve the performance of fluid flow distribution in the heat exchanger. The fluid flow distribution for the header configuration with curving perforated plate is more uniform than for the header configuration with plane perforated plate. The absolute degree of fluid flow nonuniformity in plate-fin heat exchanger has reduced from 3.47 to 0.32 by changing the header configuration. The numerical results are compared with the experimental results. They are basically consistent which indicates that the mathematical model and the calculating method are reliable.

LEAKAGES THROUGH RADIAL CRACKS IN CEMENT SHEATHS: EFFECT OF GEOMETRY, VISCOSITY AND APERTURE

2021 ◽  
pp. 1-8
Author(s):  
Ragnhild Skorpa ◽  
Torbjørn Vrålstad
Keyword(s):  
Fluid Flow ◽  
Cfd Simulation ◽  
Mechanical Damage ◽  
Simulation Software ◽  
Methane Gas ◽  
Flow Through ◽  
Cement Sheath ◽  
Well Abandonment ◽  
3D Volume ◽  
Radial Cracks

Abstract Annular cement sheath is considered to be one of the most important barrier elements in the well, both during production and after well abandonment. It is however well-known that mechanical damage to the cement sheath might result in leakage pathways, such as microannuli and radial cracks, and thus loss of zonal isolation. In this paper we have studied the effect of geometry, aperture and viscosity on the resulting pressure driven flow through real radial cracks in cement sheaths using Computational Fluid Dynamics (CFD) simulations. Real radial cracks were created by downscaled laboratory pressure cycling experiments and the resulting geometries were mapped by X-ray Computed Tomography (CT). This gave a unique 3D volume of the degraded cement sheaths which provides detailed information about the morphology, such as the irregular apertures and roughness, as well as locations of the radial cracks. In this study, we have used five experimentally created geometries, varying from barely connected to fully connected and almost uniform cracks. Additionally, theoretical uniform models with homogeneous aperture and a smooth surface were created for comparison. The simulations were performed by importing the experimentally created leak paths into a CFD simulation software, making it possible to determine the actual flowrate as a function of pressure drop. Methane gas, water and oil was used as model fluids. The simulation results show that fluid flow through real cracks in cement sheath is complex with torturous paths, especially around bottlenecks and narrow sections. Additionally, the results show that flow of both methane gas- and water are not linear and hence does not follow Darcy's law. This illustrates that simple models are not able to fully describe fluid flow through such complex geometries.

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