Seminar from Dr. Alexey MATVEICHEV


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Date | Time
09/04/2014 | All Day

Location
Salle du Conseil – IJL – Saurupt

Categories


« 3D simulation of liquid metal processing using OpenFOAM software. Application to EBM (Electron Beam Melting) process. »

Dr. Alexey MATVEICHEV, Post-doctoral IJL-Labex DAMAS

Abstract Within the framework of Work Package “Process Design” of the Laboratory of Excellence DAMAS, a study has been launched, aiming to perform actual 3D simulations of metallurgical processes involving liquid metal treatment and purification. The open-source platform OpenFOAM was chosen as the supporting software while, among several applications, we have decided to apply our modelling approach to the electron beam melting process.
Electron beam melting (EBM) is a flexible technique for remelting and purification of reactive or refractory metals. At IJL, a laboratory-scale EBM furnace is available, where liquid metal treatment is achieved in a hemispherical water-cooled Cu crucible. A liquid pool is formed inside the button-shaped metal specimen, heated by the electron beam at the free surface. While performing EBM, dissolution kinetics of additional matter introduced in the pool can be studied. Complex pattern of the surface heat source, turbulent flow, and a necessity to know the exact thermohydrodynamic behavior of the pool requires full 3D modeling of the process.
To simulate the process of EB melting, one needs to describe momentum and heat transfer, metal solidification, as well as the development of flow turbulence in the liquid. Surface heat and momentum sources and sinks such as electron beam energy deposition, thermal radiation, heat loss to the cooling circuit, surface tension (i.e. Marangoni flow) must also be addressed in the model. Therefore a new solver dealing with all the above mentioned phenomena was implemented within OpenFOAM platform.
The phase-change model was first validated by comparing computed results with previously known numerical solution of Sn melting in a square cavity. In a second stage, the full EB simulation was compared with experimental data from actual experiments of titanium melting in our electron-beam furnace. The simulations showed good agreement between modeling and experimental data.
Finally the developed model was applied to the dissolution experiments. The influence of the immersion of a refractory sample rod inside the liquid pool was simulated. Results of the simulations showed that the introduction of the cylindrical sample disturbs the flow field inside the bath. The amount of such disturbance depends on the exact location of the dipping.