The direct contact condensation (DCC) of submerged vapor jet in liquid, which has high heat and mass transfer efficiency, is widely applied in nuclear power generation, chemical engineering and aerospace. The pressure pulse generated by hydraulic instability during DCC may create periodical impulsive loads on the solid wall. It is important to evaluate pressure pulse characteristics using a wide range of inlet properties to avoid risky flow pattern regions where pressure pulses are strong. This paper presents an experimental study of the interface dynamics and pressure pulse of DCC using subsonic and supersonic steam jets condensing in water in a horizontal channel. The results reveal that pressure pulses in unstable region are caused by the contraction and expansion of the steam-water interface, while pressure pulses in stable region are caused by Kelvin-Helmholtz (KH) instability. Flow pattern transition is found to affect pressure pulse intensity. Pressure pulse intensity is minimal at the transition between the stable region and unstable region. The correlations of pressure pulse intensity in unstable and stable regions are given, respectively. The results of this study can inform the design, safe operation, and lifespan evaluation of equipment in various industrial applications that involve DCC.

液体中浸没蒸汽的直接接触冷凝（DCC）具有很高的传热和传质效率，已广泛应用于核能发电，化学工程和航空航天中。DCC期间由水力不稳定性产生的压力脉冲可能会在实心壁上产生周期性的脉冲负载。重要的是要使用广泛的入口特性来评估压力脉冲特性，以免在压力脉冲较强的情况下出现危险的流型区域。本文利用水平和垂直于水中的亚音速和超音速蒸汽喷嘴对DCC的界面动力学和压力脉冲进行了实验研究。结果表明，不稳定区域的压力脉冲是由汽水界面的收缩和膨胀引起的，而稳定区域中的压力脉冲是由开尔文-亥姆霍兹（KH）不稳定性引起的。发现流型转变会影响压力脉冲强度。在稳定区域和不稳定区域之间的过渡处，压力脉冲强度最小。分别给出了不稳定区域和稳定区域中压力脉冲强度的相关性。这项研究的结果可以为涉及DCC的各种工业应用中的设备设计，安全操作和使用寿命评估提供参考。