Development of a critical heat flux correlation based on a mechanistic model under subcooled flow boiling conditions

In this study, a mechanistic model-based correlation for the critical heat flux is proposed to meet the practical requirements for the design and safety analysis of pressurized water reactors. The correlation is based on a liquid sublayer dryout model for a single tube, which includes physical parameters, such as sublayer thickness and vapor blanket velocity, expressed as an explicit nondimensional equation and modified using a look-up table for critical heat flux to ensure a wide applicable range of coolant conditions. The correlation predicts a critical heat flux for the subcooled region in the pressure range of 0.1-18 MPa, mass velocity range of 500-8000 kg/m(2)s, and a thermal equilibrium quality ranging from -0.5 to -0.05 with high accuracy of the departure from nucleate boiling ratio limit based on a 95% probability and a 95% confidence of 1.20.