液滴热毛细迁移问题的研究进展

液滴或气泡的迁移现象无论是在流体力学的基础研究中，还是在材料加工，化学工程等实际应用中都是一个很重要的课题。在微重力环境中，如果在液滴或气泡所在的母液中外加一个温度场，则液滴或气泡就会由于表面张力分布的不均匀而发生迁移运动。这种运动被称为Marangoni迁移或热毛细迁移运动。本文综述了液滴或气泡的热毛细迁移问题历史研究中理论分析，数值模拟以及实验方面的主要结果，阐述了该问题的研究发展过程。目前液滴迁移问题的研究状况，理论分析解还只限于线性及弱非线性的定常问题，数值模拟工作已经得到了在热对流作用比较小的时候液滴的非定常迁移过程，但是对于热对流影响很大的情况(Marangoni数大于100)则尚未得到过与实验中观测到的相一致的理论结果。本文在总结前人研究的基础上，同时给出了在对于热对流作用较大时液滴热毛细迁移非定常问题的最新的数值模拟的结果，并对该问题在此情况下产生的新的变化也给予了分析。最后，文中分析了当前研究中所存在的问题并进一步展望了液滴热毛细迁移问题在未来的发展方向。 

THE PROGRESSES OF DROP THERMOCAPILLARY MIGRATION RESEARCH

The migration of bubbles ordroplets in liquids is a very important topic in materials science,chemical engineering and fundamental researches. Under themicro-gravity condition, if the temperature gradient of thebackground flow field is non-zero, bubbles or droplets will movebecause of differences in interfacial tension on the drop surface. Suchmotion is termed Marangoni migration or thermocapillary migration.In this paper, the progresses of researches on the drop/bubblethermocapillary migration, including theoretical analysis, numericalsimulation and experimental studies, are reviewed. At present, thetheoretical analyses mainly focus on linear or weaknon-linear steady problems. Some numerical simulations were carried outon unsteady migration processes of drops with the Marangoninumber less than 100. When the heat convection effect isstrong(over 100), no numerical results were reported that are consistent with those from experiments. In this paper, we summarizeprevious research results, give our new numerical resultsof unsteady drop migration problems with large Marangoni numbers anddiscuss new phenomena under this condition. Finally, some problems in current studies are pointed out and the developmentof drop thermocapillary migration problems in future is discussed.