A practical moving Gaussian temperature boundary condition for improving melt-pool width prediction in laser powder bed fusion CFD simulations

Abstract

This study investigates the effect of vapour plume-induced heating on melt pool dimensions in laser powder bed fusion by using multiphysics computational fluid dynamics simulations. In our previous simulations, the melt pool depth was in reasonable agreement with experiments, whereas the melt pool width tended to be underestimated. To examine whether this discrepancy can be partly attributed to additional surface heating associated with the vapour plume, a moving Gaussian temperature (MGT) boundary condition was introduced at the upper boundary of the computational domain. The simulations showed that the proposed boundary condition increased the melt pool width and improved its agreement with the experimental measurements compared with the conventional constant-temperature boundary condition, while the effect on melt pool depth remained limited. A three-parameter sensitivity analysis was further performed for the MGT parameters, R_vp, t_dl, and T_max, to support practical parameter setting. Within the examined parameter range, Tmax showed the largest contribution, followed by R_vp, whereas the contribution of tdl was comparatively limited. These results indicate that the proposed boundary condition provides a useful reduced representation of plume-induced heating for engineering-oriented melt pool simulations.