Jet morphology and oscillations induced by direct contact condensation of steam discharges into a water pool

Steam discharges into subcooled water pools exhibit a behavior that depends strongly on the mass flux of the injected steam and the temperature of the liquid medium, influencing the morphology and dynamic evolution of the resulting jet. An experimental study was conducted using a dedicated experimental facility, where steam is injected under controlled conditions into a pool of stagnant subcooled water, at different condensation regimes. The jet behavior is recorded using a high-speed camera, and the discharge process is analyzed through direct visualization techniques combined with an image processing methodology. Sequences of 18,000 frames are processed to extract parameters such as the mean penetration length and the maximum expansion diameter of the jet. Furthermore, the Fast Fourier Transform is applied to the time series of instantaneous jet lengths to identify the dominant frequencies associated with oscillations driven by direct contact condensation. The results reveal a transition from conical to ellipsoidal shape jets with increasing temperature and mass flux, and an exponential increase in penetration length is observed when pool temperatures exceed 70 ⁰C. Finally, empirical correlations are proposed to estimate some jet geometrical parameters, such as penetration length, and to predict oscillation frequency as a function of dimensionless variables.