Numerical Simulation of Separated Cold Gas Nozzle Flows

2004 ◽  
Vol 20 (3) ◽  
pp. 509-519 ◽  
Author(s):  
A. Gross ◽  
C. Weiland
2004 ◽  
Vol 20 (5) ◽  
pp. 879-891 ◽  
Author(s):  
A. Gross ◽  
C. Weiland

AIAA Journal ◽  
1980 ◽  
Vol 18 (9) ◽  
pp. 1088-1093 ◽  
Author(s):  
K. M. Peery ◽  
C. K. Forester

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1619 ◽  
Author(s):  
Shinichi Tashiro ◽  
Naoki Mukai ◽  
Yoshihide Inoue ◽  
Anthony B. Murphy ◽  
Tetsuo Suga ◽  
...  

This study aims to reduce the diffusible hydrogen content in deposited metal during gas metal arc welding (GMAW) and flux-cored arc welding (FCAW) which induces cold cracking. To achieve this, a novel welding torch with a dual gas nozzle has been developed. This special welding torch decreases the hydrogen source gas evaporated from a welding wire by the suction from the inner gas nozzle. In order to improve the suction efficiency of this evaporated gas, precise control of the suction gas flow is indispensable. In this paper, a simplified numerical simulation model of this process has been described. This model can take account of the evaporation of the hydrogen source gas from the wire while simulating the behavior of the shielding gas and the arc. Using this model, the effect of suction nozzle structure and torch operating conditions on suction gas flow pattern and suction efficiency was also investigated to understand the process mechanism. Furthermore, the diffusible hydrogen content in deposited metal was measured by chromatography as a validation step. Results show that some of the shielding gas introduced from a shielding nozzle was drawn inward and also branched into an upward flow that was sucked into the suction nozzle and a downward flow to a base metal. This branching height was defined as the suction limit height, which decisively governed the suction efficiency. As a result, in order to reduce the diffusible hydrogen, it was suggested that the suction limit height should be controlled towards below the wire position, where the evaporation rate of the hydrogen source gas peaks through optimization of the suction nozzle design and the torch operating conditions.


2002 ◽  
Vol 18 (1) ◽  
pp. 152-158 ◽  
Author(s):  
Ioannis G. Mikellides ◽  
Pavlos G. Mikellides ◽  
Peter J. Turchi ◽  
Thomas M. York

2020 ◽  
Vol 7 ◽  
pp. 24 ◽  
Author(s):  
Sunday Temitope Oyinbo ◽  
Tien-Chien Jen

The techniques of cold gas dynamic spray (CGDS) coating involve the deposition of solid, high speed micron to nano particles onto a substrate. In contrast to a thermal spray, CGDS does not melt particles to retain their physico-chemical properties. There have been many advantages in developing microscopic analysis of deformation mechanisms with numerical simulation methods. Therefore, this study focuses on four cardinal numerical methods of analysis which are: Lagrangian, Smoothed Particles Hydrodynamics (SPH), Arbitrary Lagrangian-Eulerian (ALE), and Coupled Eulerian-Lagrangian (CEL) to examine the Cold Gas Dynamic Spray (CGDS) deposition system by simulating and analyzing the contact/impact problem at deformation zone using ductile materials. The details of these four numerical approaches are explained with some aspects of analysis procedure, model description, material model, boundary conditions, contact algorithm and mesh refinement. It can be observed that the material of the particle greatly influences the deposition and the deformation than the material of the substrate. Concerning the particle, a higher-density material such as Cu has a higher initial kinetic energy, which leads to a larger contact area, a longer contact time and, therefore, better bonding between the particle and the substrate. All the numerical methods studied, however, can be used to analyze the contact/impact problem at deformation zone during cold gas dynamic spray process.


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