Abstract: The current study focuses on the cavitation jet characteristics of the jet nozzle for ship cleaning under different water depths. The nozzle of a dual-chamber self-excited oscillation pulsed jet nozzle is numerically studied under four depths of 10m, 25m, 50m and 100m by using the Rayleigh-Plesset cavitation model. The cavitation degree, fluid velocity distribution and turbulent kinetic energy distribution of the nozzle under different water depths are studied and analyzed. The results indicate that the cavitation in the internal flow field of the dual-chamber self-excited oscillation pulsed jet nozzle is greatest with relatively high fluid velocity and the turbulent kinetic energy is highest in the rear chamber and rear channel. However, the cavitation, fluid velocity and turbulent kinetic energy in the external flow field are significantly reduced. With the increase of the water depth, the internal flow field of the nozzle is almost unaffected, while the external flow field is greatly affected with increased cavitation number and gradually reduced cavitation degree, fluid velocity and turbulent kinetic energy, and thus weakened cavitating cleaning effect. The numerical research method can provide references for the underwater ship cavitation cleaning.

Key words: ship cleaning, self-excited oscillation, cavitation jet, water depth, numerical simulation

摘要： 为研究不同水深条件下喷嘴对船舶清洗的空化射流特性,该文以双腔室自激振荡脉冲喷嘴为研究对象,分别在10 m、25 m、50 m和100 m这4种水深条件下,应用Rayleigh-Plesset空化模型对喷嘴进行数值模拟计算,分析了不同水深对喷嘴内流场空化程度、流体速度分布、湍动能的分布规律。结果表明：在双腔室自激振荡喷嘴内流场中空化程度最大,流体速度处于相对较高的水平,湍动能在后腔室和后流道位置最大,外流场中空化程度、流体速度和湍动能明显减小;随着水深增加,喷嘴内流场几乎不受影响,但外流场影响较大,空化数增加,空化程度、流体速度和湍动能逐渐减小,空化清洗效果也随之减弱。该数值研究方法为水下船舶空化清洗提供了参考依据。

关键词: 船舶清洗, 自激振荡, 空化射流, 水深, 数值模拟