关键词: Marangoni对流, 纹影, 解吸, 界面, 传质, 浓度分布, 界面张力梯度

Abstract: A gas-liquid mass transfer apparatus and a Schlieren system were built to visualize the Marangoni convection patterns generated in the process of CO₂ desorption from ethanol in a direction perpendicular to the interface. During the desorption, uniformly-distributed and gyrate convection patterns were observed, which tend to merge and develop with time. In addition, the information such as concentration distribution and interfacial tension gradient in the mass transfer process was studied through quantitative schlieren method. The results indicate that larger interfacial tension gradient locates at the edge and center of convectional cell, drives the movement of interfacial fluid and couples with the buoyancy effect, forming the circulating flow near interface. This circulating flow leads to a concentration distribution that has higher value at the edge and lower value inside the convectional cell. This accelerates the renewal rate of interfacial fluid element so that the mass transfer is enhanced.

Key words: Marangoni convection, schlieren, desorption, interface, mass transfer, concentration distribution, interfacial tension gradient