A Multiscale Approach Simulating Generic Pool Boiling

This technical paper presents an application of the GEneralized TwO Phase flow (GENTOP) model for phase transfer and discusses the submodels used. Boiling of a heated surface under atmospheric conditions is simulated by the multifield computational fluid dynamics (CFD) approach. Subcooled water in a generic pool is heated up first in the near-wall region leading to the generation of small bubbles. Farther away from the bottom wall, larger bubbles are generated by coalescence and evaporation. The CFD simulation is based on the recently developed GENTOP concept. It is a multifield model using the Euler-Euler approach, and it allows the consideration of different local-flow morphologies, including transitions between them. Small steam bubbles are handled as dispersed phases, while the interface of large gas structures is statistically resolved. The multiscale simulation of the transitions from small bubble to larger structures during boiling in a pool is now feasible. However, the GENTOP submodels need a constant improvement and a separate, intensive validation effort using CFD-grade experiments.