Euler–Euler simulations of condensing two-phase flows in mini-channel: Combination of a sub-grid approach and an interface capturing approach

A new model implemented in the neptune_cfd code is used to study steam condensation in the presence of air in a mini-channel of opening 100µm. This model is the Full Generalized Large Interface Model. It combines a sub-grid approach and an interface capturing approach. The sub-grid approach is used to compute the small flow structures, which can be small bubbles or droplets, while the interface capturing approach is used to compute the large flow structures, which can be gas or liquid films, large bubbles or large drops. It is conceived to simulate a wide range of flow configurations, without the need for the grid cells to be smaller than the smallest flow structures. The results show that the model is able to reproduce all the flow patterns experimentally observed in mini-channels in the analyzed range of control parameters. Both the pressure drop and the Nusselt number (dimensionless wall heat flux) are found to be in good agreement with experimental correlations from the literature.