A novel smoothed particle hydrodynamics formulation for thermo-capillary phase change problems with focus on metal additive manufacturing melt pool modeling

Journal
Computer methods in applied mechanics and engineering  
Volume
381
Article Number
113812
Citation
Computer Methods in Applied Mechanics and Engineering 381: 113812 (2021-08-01)
Publisher DOI
10.1016/j.cma.2021.113812
Scopus ID
2-s2.0-85104437312
Publisher
Elsevier Science
Laser-based metal processing including welding and three dimensional printing, involves localized melting of solid or granular raw material, surface tension-driven melt flow and significant evaporation of melt due to the applied very high energy densities. The present work proposes a weakly compressible smoothed particle hydrodynamics formulation for thermo-capillary phase change problems involving solid, liquid and gaseous phases with special focus on selective laser melting, an emerging metal additive manufacturing technique. Evaporation-induced recoil pressure, temperature-dependent surface tension and wetting forces are considered as mechanical interface fluxes, while a Gaussian laser beam heat source and evaporation-induced heat losses are considered as thermal interface fluxes. A novel interface stabilization scheme is proposed, which is shown to allow for a stable and smooth liquid–gas interface by effectively damping spurious interface flows as typically occurring in continuum surface force approaches. Moreover, discretization strategies for the tangential projection of the temperature gradient, as required for the discrete Marangoni forces, are critically reviewed. The proposed formulation is deemed especially suitable for modeling of the melt pool dynamics in metal additive manufacturing because the full range of relevant interface forces is considered and the explicit resolution of the atmospheric gas phase enables a consistent description of pore formation by gas inclusion. The accuracy and robustness of the individual model and method building blocks is verified by means of several selected examples in the context of the selective laser melting process.
Subjects
Melt pool
Metal additive manufacturing
Phase change
Smoothed particle hydrodynamics
Thermo-capillarity
Two-phase flow
DDC Class
600: Technik
Funding Organisations
Deutsche Forschungsgemeinschaft (DFG)  
More Funding Information
This work was supported by a postdoc fellowship of the German Academic Exchange Service (DAAD), Germany and by funding of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within project 437616465 and project 414180263 .