Numerical Simulation of Oxidation Effects in Laser Cutting of Mild Steels

A numerical model is developed to simulate the process of oxygen-assisted laser cutting of mild steels. The coupled concentration and energy balance equations are solved by a control-volume based computational scheme while the velocity field is obtained by the analytical boundary theory. The enthalpy method is adopted to trace the free boundary of phase change. The steady-state simulation results reveal such details as the temperature profile at the cut front, the effects of impurity gas on the cutting speed, reaction energy, and heat affected zone. The striation phenomenon is simulated through the oscillation of the oxide layer caused by hydrodynamic instability. The temperature fluctuation range versus cutting speed and pressure shows similar trends as the experimental results of striation depth.