单向温度梯度下异质液滴的热毛细迁移

doi:10.12034/j.issn.1009-606X.217349

摘要/Abstract

摘要： 石蜡油与去离子水按多种比例混合形成异质液滴，放置在金属基板表面，在外加不均匀温度场作用下进行热毛细迁移，采用高速摄像机记录温度梯度驱动液滴从高温区迁移至低温区过程中液滴的形态，建立了理论模型. 结果表明，异质液滴的接触角随温度升高而减小，润湿性增强；异质液滴的迁移速度随粘度增加而减小，随温度梯度增加而增加，不同粘度下的速度差随温度梯度增大而增大，迁移速度随时间增加迅速降低，后缓慢减小到趋于0. 推导了迁移速度与Marangoni数Ma的关系式并进行了实验验证，迁移速度随Ma增加而显著增加，Ma越大，实验结果与模拟结果的匹配程度越高.

关键词: 热毛细迁移, 接触角, 温度梯度, 含水率, 粘度, Marangoni效应, 传热传质

Abstract: The phenomenon of thermocapillary migration of the heterogeneous droplets of paraffin oil and deionized water in different proportions placed on the metal substrate surface driven by the nonuniform temperature field was investigated, a theoretical model was set up. The morphological changes of the droplets driven by temperature gradient from the high temperature region to the low temperature region were recorded by high-speed camera. The results showed that the contact angle of heterogeneous droplets decreased with the rising of temperature and the wettability was enhanced. The migration velocity of heterogeneous droplets decreased with the increasing of viscosity and increased with the increasing of temperature gradient, and the difference of velocities under different viscosities increased with the increasing of temperature gradient. The variation trend of migration velocities with time decreased rapidly, and then slowly decreased to 0. The relationship between the migration velocity and the Marangoni number (Ma) was derived and verified, which indicated that the migration velocity increased markedly with the increasing of Ma. The greater the Ma was, the higher the matching degree between the experimental and simulation results were.

Key words: thermocapillary migration, contact angle, temperature gradient, moisture content, viscosity, Marangoni effect, heat and mass transfer

钟源杜海存张莹彭慧颖. 单向温度梯度下异质液滴的热毛细迁移[J]. 过程工程学报, 2018, 18(4): 697-703.

Yuan ZHONG Haicun DU Ying ZHANG Huiying PENG. Thermocapillary migration of heterogeneous droplets with unidirectional temperature gradient[J]. Chin. J. Process Eng., 2018, 18(4): 697-703.

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