Derivation and open source implementation of a simplified one-dimensional two-fluid model

Sammanfattning

Two-phase flows occur in many industrial applications, including light-water nuclear reactors,where accurate modeling of interactions between the liquid and vapor phases is crucial for safetyand efficiency.In this project, a simplified, one-dimensional, two-fluid model, consisting of mass, energyand momentum conservation equations for the liquid and vapor phases each, is derived andimplemented. Due to its simplicity and ease of use, the model is suitable for educationalpurposes and early-stage research, particularly for model development based on separate effectstests with simple geometries.The implemented code solves the six field equations in combination with simplified, yet easilymodifiable, constitutive equations. The current model can account for thermal non-equilibria,such as sub-cooled and post-CHF boiling, as well as interfacial momentum coupling betweenthe liquid and vapor phases. The systems code TRACE predicts comparable results for verticalupward flow, despite the numerous assumptions made in the simplified model.