Numerical simulation of the solidification phenomena of single molten droplets impinging on non-isothermal flat plate using explicit moving particle simulation method

Abstract

In jet engines and gas turbines, the deposition phenomenon is attributed to the adhesion of molten droplets on walls. In this study, numerical simulations of the deposition phenomena on a substrate were performed using the explicit moving particle simulation (E-MPS) method. We adopted a non-isothermal condition for the substrate using a coupling method including wall particles and a regular grid to estimate the heat conduction to and within the substrate for enhanced numerical accuracy. This coupling method was validated by comparing the theoretical values of the one-dimensional unsteady heat conduction. Simulations were performed to study the solidification phenomena of a single molten stannum (Sn) droplet impinging and solidifying on a vertical substrate. The droplet behavior from impingement to solidification shows reasonable agreement with experimental results in terms of spread factor, taking into account the heat exchange between the droplet and substrate, including the substrate temperature change. Although temperature change in the substrate is limited to areas near the impinging droplet, temperature distributions on the interface differ between the early and later stages. The high-temperature region appears near the impinging center except near the stagnation point for the former stage, while it is near the center for the latter stage. The finger and bump shapes around the impinging droplet are explained via Rayleigh–Taylor and Plateau–Rayleigh instabilities, respectively, using the actual expanding acceleration of the liquid film.