Boiling Experiments Under Microgravity Conditions
Boiling Experiments Under Microgravity Conditions
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DOI：
10.1080/08916152.2012.736850
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发表时间：
2013-03
影响因子：
3.5
通讯作者：
H. Ohta;S. Baba
中科院分区：
文献类型：
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作者：
H. Ohta;S. Baba
近50年来，利用各种微重力设备进行了大量的微重力池沸腾和流动沸腾实验。然而，重力对传热的影响并不是决定性的，因为实验结果存在矛盾的趋势，例如在有核沸腾中的气泡分离和传热特性，以及由于两相强制对流和不同蒸汽质量区域的临界热通量，重力对传热的影响未知。这可能是由于重力波动的存在和所有微重力实验固有的实验条件的限制，以及重复实验的机会有限造成的。本文对现有的实验研究进行了综述，重点介绍了池沸腾和流动沸腾的最新研究，并对本作者自20世纪90年代中期以来所做的实验进行了综述，以澄清对这一现象的不清楚认识。介绍了本文作者研制的两种用于微重力实验的实验工具，即液膜厚度测量传感器和透明加热管，并对实验结果进行了总结，特别是对气泡下微层厚度的测量和流动沸腾中重力效应的观察，包括最近的结果。此外，还介绍了计划在国际空间站上进行的空间实验，以获得重力对流动沸腾影响的相干数据，并说明了其目标和准备装置的概要。
In the past 50 years, many experiments on pool boiling and flow boiling in microgravity were conducted by using various microgravity facilities. However, the effect of gravity on heat transfer is not conclusive because there are contradictory trends of experimental results, for example, on the bubble detachment and the heat transfer characteristics in nucleate boiling, and because of the unknown effect of gravity on heat transfer due to two-phase forced convection and on the critical heat fluxes in different vapor quality regions. This might be caused by the existence of gravity fluctuation and the restriction of experimental conditions inherent in all microgravity experiments in addition to the limited opportunity of repeated experiments. In this article, the existing experimental research is reviewed, highlighting recent studies on both pool boiling and flow boiling, and the experiments conducted to date by the present authors since the mid-1990s are reviewed to clarify the unclear knowledge on the phenomena. Two experimental tools, i.e., a sensor for the measurement of liquid film thickness and a transparent heated tube, developed by the present authors for microgravity experiments, are introduced, and the results are summarized, especially on the measurement of the microlayer thickness underneath the bubbles and the gravity effect observed in flow boiling including the recent results. In addition, the space experiment planned for on board the international space station to obtain coherent data for gravity effects on flow boiling is introduced, and its objectives and outline of the prepared set-up are explained.