Vapour flow modelling in deep penetration laser welding

In most of welding processes the energy deposited at surface of the work-piece and transported inside by heat conduction. By laser beams it is deposited deeply inside a narrow cavity or a keyhole developed by the multiple reflections phenomenon. It is surrounded by the melted metal and maintained open by continuous vaporization of the material . The induced vapour pressure acts with the ablation pressure against the pressures due to the melt, avoiding the collapsing and the obstruction of the keyhole . hi our contribution , the thermodynamic parameters (ρ,p,T,v) distribution is obtained by solving a hydrodynamic system describing the behaviour of the vapour flow.