Simulation numérique directe de l’effet Leidenfrost
Lucia Rueda Villegas
Mardi 10 décembre 2013 à 10h
Sous réserve d’autorisation de soutenance par les rapporteurs
DIRECT NUMERICAL SIMULATION OF THE LEIDENFROST EFFECT
When a liquid droplet impacts on a heated surface at a temperature much higher than the liquid’s boiling point, it floats above the surface due to a vapor layer formation : this phenomenon is called the Leidenfrost effect.
In this study, we propose a direct numerical simulation of the impact of a single droplet on a heated flat surface in the Leidenfrost regime. To that end, we solve the Navier-Stokes equations, the heat equation, and the species mass fraction equation using the Level Set method to track the liquid-gas interface motion and the Ghost Fluid Method to treat the jump conditions.
Some specific numerical methods have been developed to deal with droplet vaporization interface jump conditions. A non-uniform structured grid strongly refined near the surface is used to capture the droplet bounce. To get rid of the temporal stability condition due to viscosity, an implicit temporal discretization is used to deal with viscous terms.
A new algorithm which can deal both with evaporation and boiling has also been developed to simulate the transition of regimes during the droplet bounce.
We worked on a specific simulation results analysis that enable us to study accurately the dynamics of bouncing by comparing it with experiments.
composition du jury
M. François-Xavier DÉMOULIN
M. Christophe JOSSERAND
M. Fabrice LEMOINE
M. Philippe VILLEDIEU
M. Frédéric GIBOU
M. Dominique LEGENDRE (Directeur de thèse)
M. Sébastien TANGUY (Codirecteur de thèse)