Acoustic and visual study on direct contact condensation of a steam jet in flowing water

Direct contact condensation (DCC) of steam jets in subcooled water crossflow generates intense noise that causes significant risks to energy and power systems. This investigation presents a comprehensive experimental study combining synchronous high-speed visualization and high-frequency acoustic measurements to characterize steam-water interface dynamics and acoustic characteristics during DCC, specifically focusing on sound pressure level (SPL) and dominant frequency. A novel three-dimensional condensation regime diagram is developed, incorporating the key parameters of steam mass flux, subcooled water temperature, and velocity. The results reveal that SPL exhibits non-monotonic behavior with increasing steam mass flux, initially rising to a maximum under the Oscil-I regime, then declining to a minimum under the Stable regime, and subsequently rising again. The dominant frequency follows a cubic polynomial distribution with steam mass flux, showing an initial increase before decreasing. ANOVA indicates that the linear terms (steam mass flux, water temperature, and velocity) dominated the acoustic behavior, contributing 88% and 96% to variations in SPL and dominant frequency, respectively. Notably, the interaction between steam mass flux and water temperature specifically influences SPL. Based on these comprehensive findings, empirical correlations for SPL and Strouhal number are proposed, achieving prediction errors within 5% and 20%, respectively.