Laser-produced aluminum-air plasma dynamics and chemistry: ReactingFoam modeling

When a laser pulse is directed at an aluminum (Al) target, it interacts with the surface of the material, resulting in the formation of a plasma plume. The computational fluid dynamics model is utilized to explore the chemistry of expanding plasma produced during the laser ablation of Al into an air environment composed of nitrogen (N2) and oxygen (O2) components. We employ the reactingFoam (rF) solver, which is a part of the OpenFOAM (OF) software package, to simulate the expansion of the plasma plume into the surrounding air. The appropriate thermodynamic, transport, and phase change characteristics for the Al–N2–O2 plasma are set within this solver. The results derived from rF have been validated by comparing them with published data obtained from the CHEMKIN solver, the OF rF solver, and the reacting flow solver, which employs OF and Cantera for both simulations and analytical solutions. This validation involved examination of two-dimensional temperature and velocity field. The formation of chemical compounds, specifically Al nitrides and oxides, results from the interactions among plasma species. We identified a spatial mixing boundary capable of controlling the transition from the solid Al phase to plasma with dominated chemistry. Al2O3 and AlN components are observed to be generated close to the laser spot only. The results demonstrate that thermal heating of Al can influence reaction stability and can be controlled to improve chemical reactions between species. Our findings have important implications for engineering applications, including materials science, nanofabrication, and thin film deposition.