Direct contact condensation of steam jet in subcooled water: A review

To support the design of pressure relief systems and pressure suppression systems, such as in nuclear power plants (NPPs), various experimental and theoretical investigations on submerged steam jets condensed in water pools have been carried out over the past decades, and experimental conclusions and semiempirical correlations with reasonable accuracy have been derived. Research progress in this field is reviewed systematically in this paper, including the condensation regime maps and flow patterns, the flow and heat transfer characteristics of the steam jet, and the pressure oscillations inside the discharge pipes or near the steam jet. Differences still exist in specific topics, such as the transition criteria of typical flow patterns, the determination of the steam plume length, the calculation of the heat transfer area, and the influence of noncondensable gas on pressure oscillation intensity. Nevertheless, the mechanism of local behaviour around the steam-water interface remains unclear. Therefore, special attention should be paid to these issues in future studies. In recent years, the computational fluid dynamics (CFD) technique, validated by the available experimental data through specific condensation models, has also been introduced to simulate the flow and heat transfer characteristics of steam jets, especially stable ones. It has been reported that typical steam jet shapes, temperatures and pressure profiles observed in several experiments can be reproduced by numerical simulations, with a more detailed distribution of flow field parameters of interest. Relevant achievements are also covered in this paper. The k-epsilon plus Eulerian model is the most commonly used method to address turbulence and two-phase flow, while the thermal phase-change model is usually adopted for the treatment of direct contact condensation (DCC). Finally, recommendations for future research are proposed.