The ESA/JAXA JEREMI (Japanese European Research Experiments on Marangoni Instabilities) Project

ESA/JAXA JEREMI（日本欧洲马兰戈尼不稳定性研究实验）项目

基本信息

批准号：
EP/R043167/1
负责人：
Marcello Lappa
金额：
$ 25.83万
依托单位：
University of Strathclyde
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FR043167%2F1
关键词：
ESA JAXA JEREMI Japanese European

项目摘要

The acronym JEREMI stands for "Japanese European Research Experiments on Marangoni Instabilities". This ambitious project is part of an agreement between the European Space Agency (ESA) and the Japanese Space Agency (JAXA). Started in 2001, it is now entering its final stage of preparation and is currently endorsed to fly on the International Space Station (ISS). These experiments will be executed using the FPEF (Fluid Physics Experiment Facility) of JAXA, a multipurpose facility for the investigation of fluids in microgravity. Studies of such a kind are very relevant and useful as they make it possible to observe how some physical forces, interwoven or overshadowed in normal gravity conditions (essentially the fluid surface tension and its gradients), can have a crucial impact on the behaviour of liquids (leading to the so-called "Marangoni" or thermocapillary effect). Without the complications of gravity-driven convection flows on Earth, in particular, UK scientists want to test in space fundamental theories of three-dimensional laminar, oscillatory and turbulent flows generated by these forces, which can be applied, in principle, also in a variety of "terrestrial" circumstances. More specifically, the JEREMI series of experiments is based on the so-called "liquid bridge", a drop of liquid with cylindrical free liquid-air interface held between two disks at different temperature. In space it is possible to form relatively large liquid bridges due to the absence of gravity, which would otherwise tend to deform the liquid-air interface and break the column of floating liquid. In microgravity conditions, the difference of temperature applied to the floating liquid produces buoyancy-free (purely surface-tension driven, i.e. Marangoni) convection. This type of flow is initially very regular, but it becomes oscillatory and three-dimensional if the applied temperature difference is increased beyond a given threshold. The project targets an improved understanding of this instability and the elaboration of possible means to control it by modifying the conditions at the liquid-air interface. Another objective relates to the identification of the cause-and-effect relationships at the root of the so-called "Particle Accumulation Structures" (PAS). Very recently it has been discovered that, under the effect of Marangoni flow, solid particles initially distributed uniformly in a liquid bridge can demix spontaneously from the surrounding fluid and form three-dimensional aggregates. The resulting cluster or pattern formed by particles looks like a spatially extended "closed wire" or "circuit" (having the shape of a windmill with several blades). This fascinating structure has been observed to float inside the liquid and rotate in space with constant angular velocity, thereby giving the illusion of a freely-floating "rotating solid body". An international team of scientists (from UK, Belgium, Austria, Spain and Japan) with different complementary backgrounds, expertise and perspectives, has been collaborating for more than 15 years to define precisely the set of space experiments to be executed to address the above topics. As the project is now entering its final stage, additional effort will be devoted to the elaboration of even more advanced mathematical and numerical tools to be used for the fine tuning of the experiment "input parameters" and for the interpretation of the flight results. The objective of this project is to examine experimentally and model (theoretically and numerically) fundamental physical principles still poorly known, thereby generating "new knowledge" potentially applicable in a variety of fields, which range from mechanical, chemical and thermal engineering to materials science and from the manipulation of tiny particles in small-scale systems to problems with astrophysical scale. The project aligns with the research priorities listed in the UK National Strategy on Space Environments and Human Spaceflight.

缩写 JEREMI 代表“日本欧洲马兰戈尼不稳定性研究实验”。这个雄心勃勃的项目是欧洲航天局 (ESA) 和日本航天局 (JAXA) 之间协议的一部分。该项目于 2001 年启动，现已进入最后的准备阶段，目前已获准在国际空间站 (ISS) 上飞行。这些实验将使用 JAXA 的 FPEF（流体物理实验设施）进行，这是一个用于研究微重力流体的多用途设施。此类研究非常相关且有用，因为它们可以观察在正常重力条件下交织或掩盖的某些物理力（本质上是流体表面张力及其梯度）如何对液体的行为产生至关重要的影响（导致所谓的“马兰戈尼”或热毛细管效应）。特别是，如果没有地球上重力驱动的对流的复杂性，英国科学家希望在太空中测试由这些力产生的三维层流、振荡流和湍流的基本理论，这些理论原则上也可以应用于各种“陆地”情况。更具体地说，JEREMI系列实验基于所谓的“液桥”，即在不同温度的两个圆盘之间保持具有圆柱形自由液-空气界面的一滴液体。在太空中，由于没有重力，有可能形成相对较大的液桥，否则会导致液-气界面变形并破坏漂浮液柱。在微重力条件下，施加到漂浮液体的温差会产生无浮力（纯粹表面张力驱动，即马兰戈尼）对流。这种类型的流动最初是非常规则的，但如果施加的温差增加超过给定阈值，它就会变得振荡和三维。该项目的目标是加深对这种不稳定性的理解，并制定通过改变液-气界面条件来控制这种不稳定性的可能方法。另一个目标涉及识别所谓“粒子累积结构”（PAS）根源的因果关系。最近发现，在马兰戈尼流的作用下，最初均匀分布在液桥中的固体颗粒可以自发地与周围的流体分层并形成三维聚集体。由粒子形成的最终簇或图案看起来像空间延伸的“闭合线”或“电路”（具有带有多个叶片的风车的形状）。人们观察到这种令人着迷的结构漂浮在液体内部，并以恒定的角速度在空间中旋转，从而给人一种自由漂浮的“旋转固体”的错觉。一个由具有不同互补背景、专业知识和观点的科学家（来自英国、比利时、奥地利、西班牙和日本）组成的国际团队已经合作超过 15 年，以精确定义为解决上述主题而要执行的一系列太空实验。由于该项目现已进入最后阶段，将投入更多精力来制定更先进的数学和数值工具，用于微调实验“输入参数”和解释飞行结果。该项目的目标是通过实验检验和模拟（理论上和数值上）仍知之甚少的基本物理原理，从而产生可能适用于机械、化学和热工程到材料科学和技术等各个领域的“新知识”。从小规模系统中微小粒子的操纵到天体物理规模的问题。该项目符合英国国家空间环境和载人航天战略中列出的研究重点。