Thermo-fluid dynamics of steam–water direct contact condensation in steam-filled inclined and vertical channels.

This article focuses on the computational investigation of steam–water direct contact condensation (DCC) dynamics when subcooled water is injected into steam-filled inclined and vertical channels. The study reveals that hydrodynamic instabilities—primarily Kelvin–Helmholtz and Rayleigh–Taylor instabilities—govern the flow regime transitions and interface dynamics more significantly than thermal effects. Vertical channels exhibit distinct flow regimes such as inverted annular flow and inverted plug-annular flow, with channel blockage and steam pocket formation occurring under certain conditions influenced by water injection velocity, injection diameter, and channel inclination. These findings have implications for industrial applications, notably nuclear reactor safety, where understanding and controlling flow regimes can impact heat removal efficiency and prevent structural damage due to pressure surges.