Experimental Study On Marangoni Effect On The Gas-Liquid Mass Transfer Process

Marangoni effect, also called convection driven by surface tension, is a kind of interfacial turbulence which is induced by surface tension gradient happening in the interface during the transport. Marangoni effect occurring in the interface as an effect that influences fluid stability has an important impact on chemical engineering,materials engineering,hydromechanics and space science. Further study on mass transferring process with Marangoni effect has a significant importance of improving the basic mass transfer theory and its related applications in present chemical engineering and the development of relevant cross-disciplinary.A Gas-Liquid mass transfer system with a still liquid layer was established in the first part of the paper, and the convective structures of interfacial turbulence in the mass transfer process were visualized by laser Schlieren device, then the observations were given qualitative analysis and discussion. The conclusion that increasing the scale of convection structures was in favor of enhancing mass transfer in the given system was obtained by changing the experimental conditions such as gas flow, thickness of the liquid layer, etc. The produce of different convection structures in almost the same condition and some other irregular convection structures came to the conclusion that the factors induced Marangoni effect was random. Besides, the triggering process of Marangoni effect was visualized and discussed too.In the second part, average mass transfer coefficients in different concentrations were obtained by measuring the concentration in mass transfer process of the gas-liquid system with a still liquid layer. Then the relation curve of enhancement factor and concentration gradient could be depicted, thus the relationship between enhancement factor F and Ma was obtained indirectly, and the critical Marangoni number could be determined. In this paper, the Equilibrium-Marangoni number was introduced and discussed by comparing with the critical Marangoni number.