Experimental study of interface behavior and sound pressure oscillation of direct contact condensation of a steam jet in flowing water

Direct contact condensation of a vapor jet in liquid is frequently encountered in lots of industrial applications because of its high heat and mass transfer rates. However, severe interface and sound pressure oscillation associated with condensation might cause vibration and even failure of pipeline systems. In this paper, the interface behavior and the sound pressure oscillation of a steam jet in flowing water are captured respectively by a high-speed camera and a high-frequency hydrophone. According to the gray profile of the image, an identification method is proposed to determine the interface characteristics, including the plume shape, width, and penetration length of the jet. The statistical intensity and power spectrum density of the interface position and sound pressure oscillation of the steam jet are calculated. Two typical condensation regimes of Chugging and Oscillation-I under low steam mass flux (G_s < 346 kg/m²s) are observed. The intensities of the interface oscillation and sound pressure oscillation decline with increasing steam mass flux and a significant correlation coefficient of about 0.94 between them is revealed. With the incorporation of sound pressure parameters, two correlations of the dimensionless jet length and its oscillation intensity are established, with relative deviations of 20% between the experimental and predicted values. For Oscillation-I, the dominant frequencies of the interface oscillation and sound pressure oscillation are quantitatively consistent. From the time and frequency domain perspectives, it is quantitatively confirmed that the sound pressure oscillation of the steam jet under low steam mass flux is caused by its interface oscillation.