Modeling of Droplet-Based Processing for the Production of High-Performance Particulate Materials Using Level Set Method

This research is focused on a numerical investigation of dynamic and thermal processes of single droplet in the uniform droplet spray (UDS) process. The level set method (LSM) is used to assist in tracking the liquid-gas and solid-liquid interfaces during droplet’s impingement and solidification. UDS process generates mono-size droplets of desired diameter, permits stringent control of the thermal state of the droplet, and produces deposits and materials with distinctly different microstructures including Icosahedral quasicrystalline phase (I-phase) in the Mg-Zn-Y system. The conservative level set function, combined with the Navier-Stokes and energy equations have been adopted to study the deformation and heat transfer of liquid metal droplet when impacting on the substrate under supercooling condition. The effects of surface tension and contact angle on droplet’s deformation are taken into consideration. The developed simulation technique is validated both analytically and experimentally. A rapid solidification model has been integrated with LSM to simulate the rapid solidification within the deformed Mg-Zn-Y droplet predicted in the former model. It is found that the initial temperature fields and latent heat releasing during solidification have significant impact on the solidification process.