MULTIDIRECTIONAL SOLIDIFICATION MODEL FOR THE DESCRIPTION OF MICROPORE FORMATION IN SPRAY DEPOSITION PROCESSES

This article describes a numerical investigation of micropore formatio n in solidifying molten metal droplets impinging on a colder substrate . The velocity field inside the spreading liquid droplet is computed a s a solution of the incompressible Navier-Stokes equations, and a volu me-of-fluid function is defined in order to track the location of the free surface. A multidirectional solidification model is implemented t o simulate the formation of possible pores, cavities, and/or troughs. This tracking algorithm allows for complex interface morphology repres entation as well as interface merging simulation. In the test case con sidered (high-velocity impact of a single droplet), simulations predic t the formation of an annular trough on the surface of the solidified splat. This feature may be a precursor of pore or cavity formation in multiple-droplet cases.