Investigation on Velocity Characteristics of Steam-Liquid Interface in Steam Rotating Jet

In this paper, the velocity characteristics of steam-liquid interface of steam rotating jet are studied experimentally. The dynamic behavior of the interface is captured and recorded by visualized glass window and high-speed camera. Digital image processing technology is applied to obtain quantitative interface velocity characteristics. The axial transient velocity and periodic variation of the steam-liquid interface and its characteristics are obtained. With the decrease of the steam mass flow velocity, the amplitude and fluctuation period of the interface fluctuating gradually increase; the steady flow pattern, the unstable bubble oscillation flow pattern and unstable intermittent oscillation flow patterns appear sequentially. The axial fluctuation velocity and its standard deviation of the steam-liquid interface were statistically analyzed. It was found that the supercooled water temperature increased and the interface instability was aggravated as the temperature of the supercooled water was positively correlated with the maximum value of the fluctuating velocity and the kurtosis of the fluctuating velocity. The radial average fluctuation velocity of the interface is highly correlated with the condensing flow pattern, and the average fluctuation velocity has a peak in the subsonic region.