| The ability to correctly predict the entrainment of droplets in various two-phase flow scenarios is required to effectively calculate the interfacial mass, momentum, and energy transfer, which characterizes nuclear reactor safety, system design, analysis, and performance. The present study proposes a model set to calculate the entrainment of droplets in two distinct scenarios that are characteristic to Light Water Reactor (LWR) safety analysis, droplet entrainment in co-current upward annular film flow and droplet entrainment at a quench front/froth front.; The droplet entrainment model set developed in this work is formed on the basis of a fundamental force balance and stability analyses that are coupled with control volume analyses in an effort to capture the transport and response processes related to the entrainment of liquid droplets. Additionally, an overlying interfacial drag model package has been upgraded to support the proposed entrainment model sets such that more realistic and continuous calculational results can be obtained. The model set has been developed such that it can readily be implemented into a transient three-field (continuous liquid, droplet, and vapor) systems analysis computer code. Additionally, in the development of the quench front/froth front entrainment model, an innovative means of reducing fundamental tube reflood test data has been developed that is based on ranging an unknown parameter.; The droplet entrainment and interfacial drag model set has subsequently been evaluated against a wide range of experimental data, independent from those used in the model development phase. Test data including those from annular film flow entrainment experiments, two-phase pressure drop testing, and rod bundle integral effects test data have been utilized for the model evaluation.; In conclusion, model improvements, innovations, and areas for further work are identified for the development of finite difference systems analysis computer codes which are utilized for transient two-phase fluid flow and heat transfer modeling. The basic insights gained from this study in the coupling the physics of the entrainment process with that of real-world data will be useful as a starting point for future model development and data analysis efforts involving complex heat and mass transfer phenomena like the entrainment of droplets. |
