上中国空间站“烧开水”,揭示沸腾现象中的重力作用机理

WATER BOILING ABOARD THE CHINA SPACE STATION TO REVEAL THE INFLUENCE OF GRAVITY IN BOILING PHENOMENON

烧开水是一种常见的沸腾现象,平凡之中包含着深刻而复杂的科学奥秘,对沸腾传热规律的认识支撑了以蒸汽机为标志的第一次工业革命及后续诸多工业和工程应用。沸腾过程由于相变潜热的释放具有极大的热传递能力,特别有利于热控系统的轻量化设计,对航天相关技术的发展具有重要的应用价值。沸腾现象中气、液两相介质密度的巨大差异,导致在地面常重力环境中沸腾特征往往由重力主导。航天任务所遇到的不同重力环境,对沸腾过程中的重力效应及其变化规律的研究提出了迫切需求。变重力沸腾项目是中国空间站实验舱I首批科学实验任务之一,拟针对池沸腾传热与气泡热动力学行为的重力标度规律开展研究,即利用实验舱I变重力科学实验柜提供的长时间稳定的不同重力条件,研究沸腾过程中的气泡热动力学行为及传热特性,揭示重力对沸腾现象的影响机理,构建重力标度规律,深化对沸腾传热规律的认识,支撑人类对太空奥秘的不断探索。

Water boiling in daily life is a common phenomenon of boiling,which contains profound and complex scientific mysteries.The understanding of boiling heat transfer has supported the first industrial revolution marked by steam engine and many subsequent industrial and engineering applications.Boiling process has great heat transfer capacity due to the release of latent heat of phase change,which is especially conducive to the lightweight design of thermal control system,and thus has important application potential for the development of related aerospace technology.The great difference between the density of gas and liquid phases in boiling phenomenon leads to the fact that the boiling characteristics are often dominated by gravity in the normal gravity environment on the ground.Due to the different gravity environments encountered in space missions,there is an increased demand for studying the gravity influence on boiling phenomenon.The project of vgBOILING,which is one of the first batch of scientific experimental tasks aboard the Experimental Module I of the Chinese Space Station(CSS),will study the scaling law of gravity on pool boiling heat transfer and bubble thermal dynamical behaviors.Using the long-term,stable variable gravity conditions provided by the Varying Gravity Rack(VGR)aboard the CSS Experimental Module I,the bubble thermal dynamical behaviors and related heat transfer performance of pool boiling in different gravity conditions will be studied experimentally,to reveal the influence and the underlying mechanism of gravity on boiling phenomenon,and then to construct the gravity scaling law of boiling process.The project will deepen the understanding of boiling heat transfer and support mankind's endless exploration of the mysteries of the universe.