Mechanisms of pressure pulse for condensing supersonic steam jet in a rectangular channel

Abstract

Pressure pulse is a potential risk during the application of condensing supersonic vapor jet in various industrial areas, particularly in a confined space, such as a pipe system. However, the source of pressure pulse remains unknown. In this work, experimental study on the dynamics of condensing supersonic steam jet in a rectangular channel was performed. Interface dynamics were captured by high-speed photography and quantitatively studied via an image-processing technique. The pressure pulse characteristics inside the channel were investigated using dynamic pressure transducers. Results proved that pressure pulse was caused by the growth, propagation, and detachment of interface wave induced by Kelvin-Helmholtz instability for the first time. In addition, the interface wave was proved to grow exponentially by experimental and theoretical methods. The dominant frequency was negative related, whereas its amplitude was positive related to the interface penetration length, which could be explained well by the growth, propagation, and detachment of interface wave. Finally, a prediction model for the dominant frequency was proposed on the basis of the propagation characteristics of interface wave. The proposed model could predict the dominant frequency at a maximum deviation of ±30%.