TY - GEN
T1 - The influence of surface deformation on thermocapillary flow instabilities in low Prandtl melting pools with surfactants
AU - Ebrahimi, Amin
AU - Kleijn, Chris
AU - Richardson, Ian
PY - 2019
Y1 - 2019
N2 - Heat and fluid flow in low Prandtl number melting pools during laser processing of materials are sensitive to the prescribed boundary conditions, and the responses are highly nonlinear. Previous studies have shown that fluid flow in melt pools with surfactants can be unstable at high Marangoni numbers. In numerical simulations of molten metal flow in melt pools, surface deformations and its influence on the energy absorbed by the material are often neglected. However, this simplifying assumption may reduce the level of accuracy of numerical predictions with surface deformations. In the present study, we carry out three-dimensional numerical simulations to realise the effects of surface deformations on thermocapillary flow instabilities in laser melting of a metallic alloy with surfactants. Our computational model is based on the finite-volume method and utilises the volume-of-fluid (VOF) method for gas-metal interface tracking. Additionally, we employ a dynamically adjusted heat source model and discuss its influence on numerical predictions of the melt pool behaviour. Our results demonstrate that including free surface deformations in numerical simulations enhances the predicted flow instabilities and, thus, the predicted solid-liquid interface morphologies.
AB - Heat and fluid flow in low Prandtl number melting pools during laser processing of materials are sensitive to the prescribed boundary conditions, and the responses are highly nonlinear. Previous studies have shown that fluid flow in melt pools with surfactants can be unstable at high Marangoni numbers. In numerical simulations of molten metal flow in melt pools, surface deformations and its influence on the energy absorbed by the material are often neglected. However, this simplifying assumption may reduce the level of accuracy of numerical predictions with surface deformations. In the present study, we carry out three-dimensional numerical simulations to realise the effects of surface deformations on thermocapillary flow instabilities in laser melting of a metallic alloy with surfactants. Our computational model is based on the finite-volume method and utilises the volume-of-fluid (VOF) method for gas-metal interface tracking. Additionally, we employ a dynamically adjusted heat source model and discuss its influence on numerical predictions of the melt pool behaviour. Our results demonstrate that including free surface deformations in numerical simulations enhances the predicted flow instabilities and, thus, the predicted solid-liquid interface morphologies.
KW - Free surface oscillations
KW - Thermocapillary flow instabilities
KW - Molten metal melt pool
KW - Heat source adjustment
KW - Laser melting
KW - Welding
KW - Additive manufacturing
UR - http://www.scopus.com/inward/record.url?scp=85082715646&partnerID=8YFLogxK
U2 - 10.11159/htff19.201
DO - 10.11159/htff19.201
M3 - Conference contribution
BT - Proceedings of the 5th World Congress on Mechanical, Chemical, and Material Engineering (MCM'19)
T2 - MCM '19: 5th World Congress on Mechanical, Chemical, and Material Engineering
Y2 - 15 August 2019 through 17 August 2019
ER -