High-parameter multiphase critical flow in supercritical carbon dioxide nuclear energy system

The loss-of-coolant accident (LOCA) is one of the major safety concerns in the supercritical carbon dioxide power cycle system. The precise calculation of critical flow rate during LOCA is of paramount significance as it determines the rate of coolant loss in the system. In this paper, a set of simple regenerative power cycle experimental apparatus was established, and research on high-parameter (maximum pressure:15.0 MPa, maximum temperature:500.0 °C) critical flow was carried out. The influence of thermal parameters and geometric parameters on critical flow rate was analyzed. A theoretical model of critical flow that accounts for thermal non − equilibrium phase transition and variation of the compressibility has been developed. The model accurately predicts supercritical CO₂ critical flow rates across wide parameters, with under 10 % error. The experimental data and theoretical model obtained in this research can be utilized for the safety analysis of supercritical CO₂ power cycle systems.