In the nuclear industry, simulating two-phase flows may require modeling gas pockets and/or plumes of bubbles with varying shapes. These flows transition between dispersed bubbly flows and separated regimes, characterized by large continuous interfaces, and vice versa. The challenge lies in accurately modeling the transitions between these regimes to better understand the complex phenomena that arise. Currently, two different approaches are used: a statistical method for bubbles and an interface reconstruction method for large, highly deformed bubbles or gas pockets. However, combining these methods within a unified framework remains a key scientific challenge.
The proposed PhD work aims to develop a method capable of modeling both the transitions between continuous and dispersed phases as well as their coexistence. This will involve analyzing experimental data, developing numerical tools within the NEPTUNE_CFD code, and validating the approach through academic and industrial case studies. Applications include the modeling of Taylor bubbles, the study of transitions in the METERO H experiment, and the analysis of flows in tube bundles. The expected results will enhance the simulation of these complex flows in industrial contexts.