摇摆条件对船用核动力装置凝结水射流泵空化特性影响数值研究

船用核动力装置受空间布置限制，凝结水（凝水）系统灌注高度小，凝水泵运行过程易发生汽蚀。为解决该问题，在凝水泵入口前设置凝水射流泵，以提升凝水泵入口压力、改善凝水泵汽蚀性能。然而，凝水射流泵自身也存在空化风险，特别是在摇摆条件下，凝水射流泵入口压力与流体质点受力发生变化，对凝水射流泵空化特性造成重要影响。采用计算流体力学方法，分别对凝水射流泵处于稳态工况及2种摇摆工况下的空化特性进行分析。结果表明:稳态工况下，凝水射流泵流场内空化体积分数很小，喷嘴出口与喉管前端是易空化的2个位置，工作水温升对空化特性有较大影响；摇摆条件导致凝水射流泵空化增长、扬程降低，且随着摇摆周期的减小而影响加剧；当横摇周期为3 s时，凝水射流泵出现严重空化，扬程大幅波动且显著低于额定扬程，存在完全丧失增压能力的风险，影响凝水系统运行稳定。 

Numerical Study on Effect of Ocean Conditions on Jet Pump Cavitation Characteristics for Marine Nuclear Power Plants

Owing to the limited space in the marine nuclear power plants, the lifting height for the condensate system is quite short, which can induce the cavitation of the condensate pump. To solve this problem, a jet pump is mounted in front of the condensate pump. Nevertheless, the cavitation risk also exists on the jet pump in the harsh ocean environment such as rolling motion. Therefore, the cavitation characteristics of the jet pump are investigated by CFD numerical method under the stable condition as well as two rolling motion condition. The results show that under the stable condition, the void fraction inside the jet pump flow field is very small, and the nozzle exit and throat pipe forepart are two positions prone to cavitation. Ocean rolling motion results in the enhancement of the cavitation of the jet pump and the decreasing of the lift range. The more frequent the rolling, the greater the effect. Especially, when the rolling motion period is 3 s, the cavitation of the jet pump develops seriously, the pump lift surges and is less than the rated lift evidently, which affect the operation safety of the condensate system.