PublicationsFormation of Porosities During Spot Laser Welding of Tantalum
COMSOL European Conference 2011
C. Touvrey1 , and P. Namy2
1 CEA Valduc, Is-sur-Tille, France
2 SIMTEC, Grenoble, France
The aim of the study is to predict the formation of porosities in the case of spot laser welding of tantalum. During the interaction, a deep and narrow cavity, called the keyhole, is generated. At the end of the interaction, surface tension provokes the collapse of the keyhole. Gas bubble can then be trapped into the melting pool, and give birth to residual porosities, according to the solidification time.
A model has yet been developed to simulate keyhole collapse. This model was presented at the last COMSOL European conference. The purpose of the present study is to simulate the bubble up rise. The problem is especially complex due to the high surface tension of the liquid tantalum (2.1 N.m-1).
Comparison Between Honeycomb and Fin Heat Exchangers
COMSOL European Conference 2011
P. Gateau1 , P. Namy2 , and N. Huc3
1 SAS SYNGAS, Saint Viaud, France
2 SIMTEC, Grenoble, France
3 COMSOL, Grenoble, France
Metal honeycombs are used as catalyst supports. They can be considered as complex fins for heat exchange. A simple heat transfer model was compared with 2D simulations using COMSOL Multiphysics. There was a good correlation when the fluid temperature was the same in all cells. However, significant discrepancy apperared when compared with a 3D simulation with laminar flow.
Honeycomb cells produced a temperature gradient which reduced the heat transfer. The radiant transfer was also investigated using 2D simulation. Modeling using COMSOL revealed the drawbacks of using honeycombs in steam reforming reactors. 3D modeling showed that a careful representation of the inlet was needed for realistic results.
Finite Element Analysis of Cables Heating Due to PoE/PoE+
COMSOL European Conference 2010
S. Francois1, and P. Namy2
1Nexans Research Center, Lyon, France
2SIMTEC, Grenoble, France
Power over Ethernet (PoE/PoE+) is a technology allowing to transmit data and power over the same data cable. The major concern for this technology is the degradation of data transmission performances due to the temperature increase in the cable. To have a better quantitative and qualitative knowledge of the temperature field in the cables, Nexans has developed a 2D finite element thermal model thanks the software COMSOL Multiphysics. In this model, the heat source is due to the joule effect, depending on the intensity level. This thermal model enables us to take into consideration several configurations of cable bundles and to optimize the temperature field thanks to cable design.
Level Set Method for Fully Thermal-Mechanical Coupled Simulations of Filling in Injection and Micro-Injection Molding Process
COMSOL European Conference 2009
M. Moguedet1, R. Le Goff1, P. Namy2, and Y. Béreaux3
1Pôle Européen de Plasturgie, Bellignat, France
2SIMTEC, Grenoble, France
3INSA de Lyon, Site de Plasturgie, Bellignat, France
In this work we tackle a more theoretical aspect of micro-injection molding, to better understand physics during the process, through numerical simulations of cavity filling. We developed a two phase flow approach by the use of COMSOL Multiphysics®. In a first step, a Level Set model is applied to several configurations: Newtonian and non Newtonian fluid (Cross viscosity law), coupled with a thermal equation and a thermal dependence of the viscosity (Williams-Landel-Ferry law). We take into account the unsteady thermal behavior of the mould while injecting the polymer into the cavity. Finally, as air –trapping often occurs in the injection molding process, we present some results considering a pseudocompression law (low Mach number) for the air. To conclude, we show the ability of the COMSOL model to simulate polymer filling in microfeatures.
On the Use of COMSOL Multiphysics to Understand and Optimize the Filling Phase in the Injection and Micro-Injection Molding Process
COMSOL European Conference 2007
M. Moguedet1, P. Namy2, and Y. Béreaux3
1Pôle Européen de Plasturgie, Bellignat, France
2SIMTEC, Grenoble, France
3LAMCOS, Site de Plasturgie, INSA Lyon, Bellignat, France
The work presented here deals with the simulation of the cavity filling stage of the injection and micro-injection molding process for thermoplastic materials. COMSOL Multiphysics gives us the means to take into consideration some other aspects usually neglected in commercial 3D softwares dedicated to polymer processing. In particular, tracking of the flow front is based on a Level Set approach. Results are presented for a Newtonian and non-Newtonian polymer, and in an isothermal or thermal dependant configuration. The calculations are compared to experimental results on a polypropylene.
Convective Movements in an Electrolyser
COMSOL European Conference 2007
B. Morel1, P. Namy2, C. Belhomme1, and I. Crassous3
1Comurhex, Pierrelatte, France
2SIMTEC, Grenoble, France
3LI2C, Paris, France
Modeling electrolysers is a challenge because of the strong coupling between electrical, thermal and CFD equations. Indeed the electrical conductivity of the electrolyte varies with the temperature, which in turn depends on the heat dissipated by the Joule effect and anode over-voltage.In the present study, the fluid velocity values are computed near the electrodes using a diphasic level set model, but the full calculations are performed using a monophasic model. Our goal is to evaluate the relationship between the average temperature of the cell and the average current for a given cooling surface.
