空间低重力高真空环境液体闪蒸形成的气液两相流研究

There exist severe problems relevant to liquid flashing evaporation and the induced gas-liquid two-phase flow during the process of liquid discharge into high vacuum and low gravity environment. The understanding of the basic characteristics and mechanisms of these phenomena directly affects the safety and reliability of the related space activities. Though not much, there are some researches on liquid flashing evaporation in the vicinity of the pipe outlet, which can be used for reference to help the development of the related space applied technology. There is, however, a serious lack of research on liquid flashing evaporation occurred inside the pipeline and the subsequent gas-liquid two-phase flow in the downstream complex pipeline under weak driving action in low gravity environment. By using ground simulation experimental and theoretical studies, the present project aims to study the basic characteristics and mechanisms of liquid flashing evaporation inside the pipeline and the induced gas-liquid two-phase flow in the downstream complex pipeline under weak driving action in low gravity environment. The main objectives are to obtain the inception conditions, basic characteristics and mechanisms of liquid flashing evaporation inside confined space of pipeline with small diameters, to reveal the gravity effect of the gas-liquid two-phase flow caused by the liquid flashing evaporation, the characteristics and mechanisms of the severe slugging under the weak driving action. The results will promote the progress of microgravity multiphase thermal dynamics, and will be helpful for the development of the future space liquid discharge technology in our country, especially for deep space exploration such as the lunar and Mars explorations.

空间高真空、低重力环境的液体排放过程存在着液体闪蒸及其导致的气液两相流等问题，对相关现象基本特征和规律的认识，直接关系到相关航天活动的安全性与可靠性。排放管口附近的液体闪蒸现象目前尽管也不足，但相对而言还是有一些研究成果可资借鉴，但关于低重力场中弱驱动力作用下的管内液体闪蒸及其导致的后续复杂管道系统气液两相流现象的研究尚极为缺乏。本项目拟采用地面模拟实验并辅以理论分析的方法，对低重力场弱驱动力液体闪蒸及其导致的气液两相流特性与规律进行深入研究，旨在获得小尺寸管内受限空间液体闪蒸起始条件、过程特征及其规律，揭示闪蒸形成的弱驱动力气液两相流中的重力效应、严重段塞流特征及其规律。本项目研究结果将推动微重力多相热流体动力学发展，并为我国今后航天领域（尤其是月球和火星等深空探测活动）空间液体排放技术研发服务。

空间高真空、低重力、冷黑等独特环境中的液体排放过程中，闪蒸的发生及由此形成的极为复杂的气液两相流现象，将大大增加液体排放问题的复杂性，影响航天活动的安全性与可靠性，甚至危及航天任务的顺利执行。我国嫦娥5号月球探测任务中就面临着该技术挑战。因此，对空间环境液体闪蒸及闪蒸导致的气液两相流现象及其规律的研究，有着重要的科学意义和重大实用价值。.本项目实验研究了空间高真空、低重力环境下闪蒸现象及其引起的气液两相流现象，获得了闪蒸界面的传播以及闪蒸引起的气液两相流（严重段塞流）流动特征与规律。并揭示弱驱动力气液两相流中的重力效应，拓展气液两相流主导作用力分区准则。助力解决空间环境中的高真空和多重力（尤其是低重力或部分重力）条件下液体的排放过程遇到的问题，并服务于我国航天事业（尤其是国际竞争日益激烈的月球和火星等深空探测活动）。