Modelling and simulation of flow boiling with an Eulerian-Eulerian approach and integrated models for bubble dynamics and temperature-dependent heat partitioning

A time-averaged Eulerian-Eulerian (E-E) multiphase approach for the simulation of boiling flows is presented. A previously developed bubble dynamics model is implemented in the E-E framework as a sub-model to improve the accuracy of the simulations and reduce the case dependency. This mechanistic model, which is based on the balance of forces applied on a single bubble, considers the evaporation of the microlayer underneath the bubble, thermal diffusion and condensation around the bubble cap as well as geometry changes and dynamic inclination and contact angles. The advantage of this model is that it does not require a recalibration of parameters to predict the bubble departure size. However, its implementation in the E-E framework needs an extension of the current nucleation site activation and heat partitioning model. Further on, we use a population balance model in our approach.