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.