Multiscale approach for boiling flow simulation

Numerical modeling of boiling flow is challenging due to the wide range characteristic lengths of the physics at play: from nano/micrometers bubble nucleus to sub-meters flow pattern, particularly, when the role of the nano/micro surface structure attracts more attention recently. To address this, we present here our activities in multiscale approaches e.g the Euler Euler (EE) of boiling flow considering the bubble void fraction distribution and GEneralized TwO Phase flow (GENTOP) model to simulate the large free surface structure, the Direct Numerical Simulation (DNS) of bubble dynamics considering detailed surface structure, the Molecular Dynamics (MD) simulation of bubble static/dynamics wetting, and also the bridging concept between each scale activities. The works are demonstrated on several problems including the contact line region of a nucleation bubble, microlayer beneath the bubble, bubble dynamics on a structured surface, bubble population balance, interfacial forces between dispersed phases, and free surface. These activities highlight the capability of the developed multiscale concept to enhance the robustness of boiling flow simulation, though whose application in nuclear-related processes should be an industry-oriented theme that should be with low time and computer hardware requirements.