Experimental Investigation of Single Bubble Nucleate Boiling in Microgravity
Experimental Investigation of Single Bubble Nucleate Boiling in Microgravity
复制标题
DOI：
10.1007/s12217-020-09813-z
复制
发表时间：
2020-07
影响因子：
1.8
通讯作者：
I. Nejati;A. Sielaff;Benjamin Franz;M. Zimmermann;Philipp Hänichen;K. Schweikert;Julian Krempel;P. Stephan;Anne Martin;H. Scheerer;T. Engler;M. Oechsner
中科院分区：
文献类型：
--
作者：
I. Nejati;A. Sielaff;Benjamin Franz;M. Zimmermann;Philipp Hänichen;K. Schweikert;Julian Krempel;P. Stephan;Anne Martin;H. Scheerer;T. Engler;M. Oechsner
多尺度沸腾项目，又称RUBI，是由欧洲航天局(欧空局)支持的一项实验项目，重点是在利用国际空间站(ISS)的框架内进行原子核沸腾。为了研究实验部件的工作行为，确定一个有前景的参数范围，在欧空局第70次抛物线飞行战役的框架内，构建了一个具有相同加热器设计的实验装置，并在相似的参数范围内进行了测试。本文介绍了实验装置和测量方法。它集中于在没有电场或剪切流等外力的情况下核态沸腾的结果，这些外力也是多尺度沸腾工程的一部分。一块在氮化铬层顶部溅射出铬的氟化钡玻璃用作加热器。详细介绍了加热器基板的制造工艺。为了在过冷液池中产生汽泡，激光被用来在玻璃中心的人工成核处提供必要的热量。该实验装置允许在加热器开启和激光发射之间进行时间调整，该时间被定义为预热时间。研究了预热时间对气泡形核和行为的影响。此外，通过选择较长的激光脉冲宽度，研究了激光热能对气泡生长的影响。结果表明，预热时间对气泡的生长有显著影响。然而，即使在较长的脉冲宽度下，激光脉冲对气泡的生长也没有影响。
Themultiscale boilingproject, also known as RUBI, is an experimental project supported by the European Space Agency (ESA) focusing on the nucleate boiling within the framework of the utilization of the International Space Station (ISS). In order to investigate the operational behavior of the experimental components and determine a promising parameter range, an experimental setup with the same heater design is constructed and tested within the similar parameter range in the framework of the ESA 70thparabolic flight campaign. The present work introduces the experimental setup as well as the measurement methodologies. It concentrates on the results obtained for the nucleate boiling in the absence of external forces such as electric field or shear flow, which are also part of themultiscale boilingproject. A barium fluoride glass sputtered with chromium on the top of a chromium nitride layer served as the heater. The manufacturing process of the heater substrate is presented in detail. In order to generate a vapor bubble in the subcooled liquid pool, a laser beam is used to provide the necessary heat at an artificial nucleation site situated at the center of the glass. The experimental setup allows for time adjustment between switch-on of the heater and shooting the laser which is defined as preheating time. The effect of the preheating time on the nucleation and behavior of the bubbles is investigated. Furthermore, by selecting a long laser pulse duration the influence of the laser thermal energy on the growth of the bubbles is studied. It is observed that the preheating time has a significant effect on the bubble growth. However, no influence of the laser shot is detected on the bubble growth, even for a long pulse duration.