Direct numerical simulation of phase change in turbulent two-phase flows : application to HIT and cryogenic tanks
Despite the intense research being carried out in numerical methods in fluid mechanics, there are still areas with numerous applications that have not been completely mastered. Heat and mass transfer near a liquid-gas interface deformed by turbulence is one of the targets that needs to be reached if we want to simulate correctly, for example, the boiling phenomenon in cryogenic tanks (boil-off), cooling and heat transfer systems in nuclear power plants or multiphase chemical reactors.
These reasons prompted us to develop in our in-house DNS code ARCHER advanced numerical methods able to represent accurately heat and mass transfer at a liquid-gas interface. Recently, the mass-conservative interface capturing (Coupled Level Set/VOF) methods have been adapted to account for the liquid mass variation due to phase change in incompressible and compressible turbulent flows [1].
In this work, the compressible Navier-Stokes equations are solved using a pressure-based method with appropriate jump conditions at the interface, which allows us to capture the Stefan flow at the liquid/gas interface, acoustic effects, and the thermal dilatation of both phases.
Results obtained with this formalism for a compressible vaporizing two-phase HIT and a sloshing configuration with LH2 will be shown and discussed during this talk, illustrating the method’s potential and highlighting the new data available with this method.
DNS of a sloshed LH2 tank with imposed heat fluxes at the lateral and top boundary (ϕ=50 W.m^(-2) ). The boiling rate is represented on the liquid-gas interface.
[1] L. Germes Martinez, B. Duret, J. Reveillon, F.X. Demoulin, A new DNS formalism dedicated to turbulent two-phase flows with phase change, International Journal of Multiphase Flow, 143, 103762, 2021.
Contact Nathanaël Machicoane for more information or to schedule a discussion with the seminar speaker.