低温流体节流过程空化现象的形成与发展规律

文章将rng 湍流模型与完全空化模型相结合,对孔板节流所导致的低温流体空化流动进行数值模拟,得出了流场中的含气率与压力分布的变化规律.数值模拟研究还发现:由于孔板节流作用使得流场中最低压力出现在孔板喉部,并在此位置出现空化初生点;在低温空化流动中,泡状空化、云状空化、超空化3种空化形态相继出现.分析了空化初生点的压力以及含气率的变化规律,得出了3种空化形态的气相组成;分析了3种空化形态的初生标志,对临界空化状态进行了界定.

Inception and growth of cavity in throttling flow for cryogenic fluid

This paper discusses the inception and growth of cavity in cavitating flow of cryogenic fluid induced by orifice throttling, and presents results of the numerical simulation by combining the full cavitation model and the RNG turbulence model. The vapor fraction and the pressure distribution in cavitation region are examined. The computation results indicate that the cavitation inception spot appears in the wall of an orifice sharp corner due to its lowest pressure in the whole passage. And then, the bubble cavitations, cloud cavitations and super cavitations consecutively occur with a gradual enhancement of cavitations of cryogenic fluid by modulating throttling flow. Moreover, the vapor fraction and the pressure distribution in the three stages of cavitations are studied, and the gaseous compositions in the three stages of cavitations are examined. The paper gives a criterion of regime transition for the three stages of cavitations, and verifies the critical cavitations, which provides a foundation for further researches.