Numerical analysis of bubble condensation behavior under high-pressure flow conditions

Abstract

Heat transfer during subcooled flow boiling has a pivotal role in pressurized water reactors; it also occurs in boiling water reactors prior to the onset of saturated nucleate boiling. We examined the condensation behavior of vapor bubbles in the subcooled liquid phase using the fully compressible two-phase homogeneous mixture method, solved by an implicit dual-time preconditioned method. The continuous surface force method was applied to determine the surface tension between the phases in the simulation. To predict the empirical coefficient, we conducted a sensitivity study using Lee’s mass transfer model. For nuclear applications, we simulated high-pressure vapor–water conditions under higher mass flow conditions. The comparison of the numerical simulation and experimental results showed that the proposed model accurately predicted the condensation behavior of the bubble. Additionally, we investigated single bubble condensation behavior at different operating pressures, subcooling temperatures, bubble diameters, and bulk velocities. We also investigated the effects of high-pressure condensation on bubble shape. At lower subcooling temperatures, the condensation rate increased as pressure increased; however, at higher subcooling temperatures, pressure had no significant impact on the condensation rate.