Numerical study on the effect of pressure and nozzle dimension on particle distribution and velocity in laser cladding under vacuum base on CFD

• The first time simulation work in laser cladding process under vacuum.
• A optimized nozzle dimension is proposed by simulation method.
• A convergence powder flow can be found in LC process under vacuum.
• The carrier gas as Helium can lead to an over high particle velocity.

Numerical study was conducted to investigate the effect of environment pressure and nozzle dimensions on particle distribution and velocity in laser cladding by using three-dimensional models based on computational fluid dynamics. The simulation results show that the vacuum environment can lead to a high particle velocity and convergent powder flow during laser cladding. It was found that the nozzle dimensions have significant effect on particle distribution and velocity. A more convergent powder flow can be obtained when used 60° nozzle degree. Moreover, by decreasing the focus length, the powder flow concentration can be increased, which results in a high powder feeder delivery efficiency. In additional, the Helium carrier gas can steeply accelerate the particle to a high velocity during laser cladding process under vacuum.