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

摘要： 建立了一套气液传质装置和一套纹影系统对乙醇解吸CO₂过程中产生的Marangoni对流结构进行垂直界面方向上的观察，发现解吸过程中近界面处出现均匀分布的旋涡状的对流结构，并随时间聚合发展变大。此外还利用定量纹影法考察了传质过程中的浓度分布和界面张力梯度等信息。定量的结果表明较大的界面张力梯度位于对流胞型的边缘和中心处，驱动着界面流体的运动，并耦合浮力效应，形成了近界面环流的运动形式。这种环流运动造成了对流胞型边缘浓度较大、内部浓度小的分布，促进了相界面流体微元的更新，加强了传质过程。

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