Numerical simulation of current density in gas tungsten arc welding including the influence of the cathode

1997 ◽  
Vol 211 (4) ◽  
pp. 321-327 ◽  
Author(s):  
H G Fan ◽  
S-J Na ◽  
Y W Shi
Keyword(s):  
Experimental Data ◽  
Current Density ◽  
Current Density Distribution ◽  
Anode Current Density ◽  
Arc Plasma ◽  
Plasma Cathode ◽  
Current Electrode ◽  
Density Distributions ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

A two-dimensional axisymmetric numerical model including the influence of cathode is developed to describe the heat transfer and fluid flow in gas tungsten arc (GTA) welding arcs. The current continuity equation has been solved with the combined arc plasma-cathode system, independent of the assumption of current density distribution on the cathode surface which was essential in the previous studies of the arc plasma. It is indicated that the predicted arc column temperatures agree well with existing experimental data. The effects of current, electrode tip geometry and arc length on the anode current density distributions are analysed using the developed model, and the current density distributions calculated at the anode are compared with the experimental data measured by the probe method.

A numerical analysis of a gas—tungsten arc welding considering the current density and temperature distribution on the electrode surface

2002 ◽  
Vol 216 (8) ◽  
pp. 1115-1121 ◽  
Author(s):  
J H Lee ◽  
Y T Cho ◽  
S-J Na
Keyword(s):  
Temperature Distribution ◽  
Numerical Analysis ◽  
Current Density ◽  
Electrode Surface ◽  
Arc Welding ◽  
Current Density Distribution ◽  
Arc Plasma ◽  
Accurate Analysis ◽  
Gas Tungsten Arc ◽  
Distribution Parameters

In numerical analysis of an arc plasma, the current density distribution and temperature distribution along the electrode surface are the most important boundary conditions, and a more accurate analysis can be achieved with a correct description of them. It was found that a distributed temperature condition taken from measured data makes isothermal contours broaden. The current density on the electrode surface was assumed to have a Gaussian distribution and its distribution parameters could be calculated for various electrode vertex angles. Analytically calculated distribution parameters helped the calculated temperature contours of the arc plasma to conform fairly well with experimental data.

Modeling of Transport Phenomena in Gas Tungsten Arc Welding Arc

2012 ◽  
Author(s):  
X. Yang ◽  
J. Hu ◽  
J. Pallis
Keyword(s):  
Weld Pool ◽  
Current Density ◽  
Arc Welding ◽  
Transport Phenomena ◽  
Gas Tungsten Arc Welding ◽  
Anode Surface ◽  
Arc Plasma ◽  
Gas Tungsten Arc ◽  
Arc Model ◽  
Gas Tungsten

This paper developed a mathematical model to simulate the transport phenomena in the arc plasma of a gas tungsten arc welding (GTAW) process. The arc model simulated the electromagnetic field in three regions — cathode, arc plasma, and anode; and heat transfer and fluid flow in the arc region. The temperature, velocity, pressure, current density and electromagnetic fields are explored in the arc plasma region to study the arc plasma characteristics. The distributions of heat flux, current density, arc pressure and plasma shear stress at the anode surface are obtained as boundary conditions for weld pool models. The predicted results are compared with published results. The developed arc model will be coupled with a weld pool model to study the interaction between arc plasma and weld pool.

Mixing of multiple metal vapours into an arc plasma in gas tungsten arc welding of stainless steel

2017 ◽  
Vol 50 (43) ◽  
pp. 43LT03 ◽  
Author(s):  
Hunkwan Park ◽  
Marcus Trautmann ◽  
Keigo Tanaka ◽  
Manabu Tanaka ◽  
Anthony B Murphy
Keyword(s):  
Stainless Steel ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Arc Plasma ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

Real-time observation of cathodic cleaning during variable-polarity gas tungsten arc welding of aluminium alloy

2009 ◽  
Vol 223 (9) ◽  
pp. 1143-1157 ◽  
Author(s):  
R Sarrafi ◽  
D Lin ◽  
R Kovacevic
Keyword(s):  
Real Time ◽  
Process Parameters ◽  
Arc Welding ◽  
Molten Pool ◽  
Gas Tungsten Arc Welding ◽  
Process Conditions ◽  
Current Electrode ◽  
Gas Tungsten Arc ◽  
Variable Polarity ◽  
Gas Tungsten

Online observation is expected to provide a better understanding of the cathodic cleaning of oxides from the molten pool during variable-polarity gas tungsten arc welding (VP GTAW) of aluminium alloys. In this paper, a machine-vision system with appropriate illumination and filtering is used to monitor in real time the effect of different process parameters on the cleaning of oxides from the molten pool during VP GTAW of Al 6061. Based on the observations, the process conditions under which a clean molten pool can be achieved are determined. In addition, the control of the welding process to maintain the consistency of cathodic cleaning is discussed. The results showed that in order to have an oxide-free molten pool, the solid surface in front of the molten pool should be cleaned from oxides by the electric arc. The choice of process parameters to satisfy this condition has been discussed. It was found that the percentage of direct current electrode positive (DCEP) polarity in the cycle of current has the highest impact on the cathodic cleaning, with the arc current having less influence, and the welding speed showing the least effect. Furthermore, in order to keep the consistency of oxide cleaning, process parameters should be set or controlled to maintain the cleaned zone larger than the molten pool.

Experiment Design with Full Factorial in Gas Tungsten Arc Welding Parameters on Aluminium Alloy 5083

2013 ◽  
Vol 711 ◽  
pp. 183-187 ◽  
Author(s):  
Prachya Peasura
Keyword(s):  
Arc Welding ◽  
Parent Phase ◽  
Welding Current ◽  
Alternating Current ◽  
Gas Tungsten Arc Welding ◽  
Welding Parameters ◽  
Current Electrode ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Full Factorial

This research was to study of gas tungsten arc welding (GTAW) welding parameters that affects to the mechanical properties of aluminum alloy AA5083 welding with GTAW. The full factorial design was experiment. The factors was study in type of polarity on alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), levels of welding current for 180,200,220 and 240 amp. The specimen to analyses the physical properties has microstructure and hardness of weld metal and heat affected zone. The result showed that type of welding current and levels of welding current interaction hardness at the level of confidence 95% (P-value<0.05). The factor hardness maximum of weld metal was alternating current at level of current 240 amp. and hardness of 136.53 HV. The factor hardness maximum of HAZ value was alternating current at level of welding 220 amp. and hardness of 169.43 HV. The welding parameters can result in increasing Mg2Si intensity in parent phase. It can also be observed that Mg2Si at the parent phase decreased due to high welding current in HAZ.This research can be used as information in choosing how to welding parameter for gas tungsten arc welding of aluminum alloy.

Modeling PEMFC With FLUENT: Numerical Performance and Validations With Experimental Data

2005 ◽  
Author(s):  
Shaoping Li ◽  
Jing Cao ◽  
William Wangard ◽  
Ulrich Becker
Keyword(s):  
Experimental Data ◽  
Fuel Cell ◽  
Current Density ◽  
Mass Fraction ◽  
Polarization Curves ◽  
Local Current Density ◽  
Density Distributions ◽  
Local Current ◽  
Numerical Performance ◽  
Good Agreement

A 3-dimensional, two-phase Computational Fluid Dynamics (CFD) model for PEMFC simulations has been developed and implemented in FLUENT, a general-purpose commercial software package with multi-physics capabilities. The model formulation was given in details in the previous ASME fuel cell conference, together with in-situ distributions of current densities and species concentrations computed for a simple geometry. In this paper, numerical performance of this model in terms of computing time and parallel efficiency are assessed through the computation of a relatively larger-size fuel cell (50 cm2) with serpentine channels. The convergence history and parallel performance data show that the Fluent’s PEMFC model is numerically robust and efficient. In addition to the numerical performance, the physical validity of the model is tested through comparisons with experimental data of polarization curves and local current density distributions from the most recent work of Mench et al [1]. Comparisons with the data show good agreement in the overall polarization curves and reasonably good agreement in local current density distributions too. The comma-shaped local polarization curves seen in the experiments are qualitatively correctly captured. Moreover, our computations show that hydrogen mass fraction and molar concentration can both increase along the anode flow channel, despite that hydrogen is being depleted in the anodic electrochemical reaction. The reason for this to happen is that the osmotic drag moves the water from anode to cathode at a much faster rate than the hydrogen depletion rate. An analytical derivation that reveals the relationship between species molar concentration and mass fraction is also given.

Transient Multi-Field FEA Model for Predicting Current Density Distribution When Deforming Sheet Metal Under a Direct Current

2008 ◽  
Author(s):  
John T. Roth ◽  
Amir Khalilollahi ◽  
Daniel J. Jageman
Keyword(s):  
Temperature Distribution ◽  
Density Distribution ◽  
Sheet Metal ◽  
Current Density ◽  
Three Dimensional ◽  
Current Density Distribution ◽  
Electrode Placement ◽  
Dome Height ◽  
Current Electrode ◽  
Fea Model

Previous investigations have been performed that involve developing new ways in which to deform a material while minimizing the energy required to do so. More recent research involves applying an electric current to the workpiece to achieve superplasticity. However, those investigations only utilized uniaxial workpieces and lack the ability to be used for more common geometries. The research presented herein, however, the effect is investigated under three-dimensional conditions so that the results could be projected to more realistic sheet metal geometries. A working finite element analysis (FEA) model has been developed to analyze these more complicated three-dimensional flow fields and will be presented as a part of this research. The model was used to solve for the temperature and current density distributions across the workpiece. The results from the FEA model are compared to results obtained from experimental tests. In the experimental setup, the two dome heights were separately tested under the same conditions that the FEA model simulated, however, only a temperature distribution was obtained here. The comparison of the FEA results and the experimental results related the temperature distribution to the current density distribution across the workpiece. From here, the individual effects of certain parameters on the distributions were found. The parameters included: duration of current, amount of current, electrode placement, and dome height geometry. The results showed that the current density distribution can be manipulated by varying the above parameters. This capability can be used to delay tearing/necking of a sheet metal workpiece under deformation.

Driving Force Variation in Weld Pool Affected by Current Density and Flow Velocity of Gas Tungsten Arc Welding

2012 ◽  
Vol 132 (5) ◽  
pp. 486-492 ◽  
Author(s):  
Tadashi Sakai ◽  
Hiroyuki Taki ◽  
Toru Iwao ◽  
Shinichi Tashiro ◽  
Manabu Tanaka ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Weld Pool ◽  
Current Density ◽  
Arc Welding ◽  
Driving Force ◽  
Gas Tungsten Arc Welding ◽  
Gas Tungsten Arc ◽  
Force Variation ◽  
Gas Tungsten
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