Introduction
In recent years the importance of Selective Laser Melting (SLM) has grown rapidly. The simulation of SLM process has been performed in different ways, such has: Finite Elements Method (FEM), Particles Method (PM), Lattice Boltzmann Methods (LBM). In particular LBM are a relative new method that purposes to solve the Navier-Stokes equation by starting from the Boltzmann equation. In recent articles many authors purposes to include the heat transfer in LBM in order to simulate the SLM process. This method is presented to be particular suitable for its capability to adapt to complex geometry and for the simplicity to impose boundary conditions.
Goal
Our study purposes to overcome the principal difficulties presented in the literature references for LBM Methods, such as the correct heat transfer between different phases and including the phase change in the model. The final goal of this study is to be able to predict the correct thermal behaviour of the melted material and to calculate with a certain precision the stress distribution after the re-solidification of the liquid material.
Video 1: DROPLET WETTING of two droplets on a smooth surface. Realized using Shan-Chen single component multiphase approach. Adhesion force has been included using the potential approaach proposed by Doolen.
Video 2: DROPLET WETTING of a droplet on a smooth surface, with temperature variation. Realized using Shan-Chen single component multiphase approach coupled with the multiphase thermal lattice Boltzmann scheme.
Next Steps
In order to simulate the melting process of small particle, the next step of our work will be to include in the developed Lattice Boltzmann scheme the phase change that will be implemented using a multidistribution enthalpy based approach for the treatment of the thermal problem.
Fig. 1: Example of metal powder bed fusion process carried out at the Lawrence Livermore National Laboratory (LLNL) with the ALE3D software.
References
- Wang, Jinku, Moran Wang, and Zhixin Li. “A lattice Boltzmann algorithm for fluid–solid conjugate heat transfer.” International journal of thermal sciences46.3 (2007): 228-234.
- Körner, Carolin, Elham Attar, and Peter Heinl. “Mesoscopic simulation of selective beam melting processes.” Journal of Materials Processing Technology211.6 (2011): 978-987.
- Li, Qing, et al. “Lattice Boltzmann methods for multiphase flow and phase-change heat transfer.” Progress in Energy and Combustion Science 52 (2016): 62-105.
- King, W., et al. “Overview of modelling and simulation of metal powder bed fusion process at Lawrence Livermore National Laboratory.” Materials Science and Technology 31.8 (2015): 957-968.