Analysis of two-phase flow characteristics in a natural circulation loop using the drift-flux model taking flow pattern change and subcooled boiling into consideration

This study investigated the steady-state characteristics of a two-phase natural circulation loop based on the drift flux model, taking flow pattern change and subcooled boiling into consideration. Transcendental equations of non-dimensional loop mass flow rate under various conditions were also derived. The model proposed herein was verified by comparing our results with experimental data found in literature. In addition, various steady-state characteristics of a natural circulation loop were analyzed and discussed; these characteristics include the one-third-power dependence of the single phase mass flow rate on heating power, the incipient power of two-phase flow, the maximum mass flow rate, and the existence of multiple solutions under certain conditions. This study also examined the effects of changing important parameters.