Momentum induced by steam injection into a subcooled pool

• Published in: International journal of heat and mass transfer Vol. 232; p. 125969
• Main Authors: Wang, Xicheng, Kudinov, Pavel, Grishchenko, Dmitry, Puustinen, Markku, Räsänen, Antti, Kotro, Eetu, Pyy, Lauri
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2024
• Subjects: Direct contact condensation; Effective momentum; Jakob number; Mach number; Pitch-to-diameter ratio; Sparger; Pitch-to-diameter ratio; Effective momentum; Jakob number; Sparger; Direct contact condensation; Mach number
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2024.125969

•Momentum rate induced by steam injection into a subcooled water is measured.•Correlation for condensation regime coefficient by Jakob and Mach numbers.•Rapid increase of instantaneous force at low Jakob number.•Significant effect of pitch-to-diameter ratio on time-averaged momentum and instantaneous force.
Boiling Water Reactors (BWR) and Advanced Pressurized Water Reactors (APWR) often use spargers to release steam from the primary coolant system into a pool with subcooled water to prevent containment overpressure. Direct contact Condensation (DCC) creates sources of mass, heat, and momentum determined by the condensation regimes in a subcooled pool. Thermal stratification can develop in the pool if buoyancy forces created by the heat source dominate the momentum source. Only part of the stratified pool volume can be used as the heat sink which is a safety concern. Modeling of steam injection and its effect on a large pool is computationally expensive due to the considerable spatial and temporal scale differences between the steam-water interface dynamics and global pool circulation. To enable the prediction of realistic plant transients, Effective Heat Source (EHS) and Effective Momentum Source (EMS) models were proposed. These models aim to calculate the time-averaged integral effects of the steam injection on the pool without resolving the dynamics of the interface and DCC phenomena.
This work aims to develop the empirical correlations that predict the time-averaged effective momentum induced by steam injection into a subcooled pool. The experimental data were collected in a Separate Effect Facility (SEF-POOL) at LUT, Finland. The force acting on the injection pipe was measured in SEF-POOL to estimate the effective momentum rate created by steam injection. The condensation regime coefficient C, defined as the ratio of effective momentum rate to the theoretical momentum rate of injected steam, is presented as a function of Jakob and Mach numbers. We found that the pitch-to-diameter ratios (P/D) had a significant effect on both the effective (time averaged) momentum rate and instantaneous forces measured in the low Jakob number region, which might be attributed to the interactions between neighboring nozzles.