蒸发效应与热毛细对流耦合现象的实验研究

实验研究了矩形液池中蒸发薄液居中蒸发效应与热毛细对流的耦合机理. 对于单纯的热毛细对流稳定性从实验和理论上已有深入研究，但目前国际上对带有菇发界面的热毛细对流问题尚缺乏研究. 特别是近来的研究发现，气液界面的蒸发对热毛细对流稳定性有很大的影响. 本实验以温度为主要控制参数，测量了不同工况下蒸发界面不同点的蒸发速率和表层温度，并利用 PIV 方法分析得到了液体内的嘛场分布. 实验结果发现，随着沿界面的温差增加，蒸发液体内的流型从稳定的单涡胞结构变为稳定的多祸胞结构，并最终演变为紊流结构. 综合分析以上测量结果并与理论分析结果进行了比较。 

Experimental Study on the Coupling of Thermocapillary Convection and Evaporation Effect in a Liquid Layer

There has been a variety of applications for therm ocapillary convection and evaporation,such as t1iin-film evaporators, boiling teclinologies and heat pipes. And the stab ilities of therm ocapillary convection in a fluid layer subjected to a liorizontal temperature gradient have been experimentally and nulnerically analyzed by many scientists. While tlie inter I : acia I flow with evaporation,whic1i is a classical physical phenomenon, is absent of comp re1iensive understanding. Recently, many theoretical and experimental researcbes have found that evaporation plays a very important role inthe instabilities of therm ocapilllary convection. In our experiment, we study the coupling of the omcapillary convection and evaporation effect Ilor 0.65 cst Silicone Oil as the experimental liquid in a recta ngitlar cavity which has the I engtli of 0.08 m and width of 0.04 m. The temperature gradientalong the liquid layer, which induces t1ie therm ocapillary convection, is the dominate parameter. The temperature at the interface and the evaporating rate are measured by a thermocouple and a laser co focal displacement meter, respectively. The PIV metbod is applied for flow visualization, and the flow pattern transforms from a steady unicellular flow to a steady multicellular fiow, to a turbulent flow ultimately with the temperature difference along the interface increases from 2o C to l4o C . For discussion, the experimental results are compared wit1i linear stability analysis.