Marangoni effects, studying processes

In the study of mass transfer, the fluid element (microcell) can be used to describe the behaviors of the process. Under the condition of no Marangoni effect, according to the penetration theory, the fluid element flows randomly from fluid phase to the interface and stays there within residence time T for unsteady mass transfer and then go back to the bulk fluid. The liquid-phase mass transfer coefficient is given by the following ... 

Yu LM (2005) The study of Marangoni effect on the gas liquid mass transfer process. PhD dissertation, Tianjin University, Tianjin, China (in Chinese)... 

Lewis Pratt, in 1953, were the first to report that the observed Marangoni convection in their experimental ternary systems was beneficial to hquid-hquid extraction processes because it increased mass transfer rates. The effect of density gradients on interfacial convection was studied by several researchers including Berg Morig (1969), who investigated the interaction between buoyancy and interfacial tension driven effects in ternary systems. The combined interfacial convection was also seen to be beneficial to mass transfer processes. 

Moreover, all mass transfer processes involve the diffusion through the interface between adjacent phases. Interfacial effects, such as the Marangoni convection and the Rayleigh convection, cannot be ignored. Thereftffe, the study of interfacial effects is another important aspect of CMT. 

To find the exact value of the exponent n in Eq. (9), three different effects have to be considered the influence of the parameter B related to the unsteady nature of the process the already discussed relationship between n and the circulation intensity and the possible response to B regarding the wide range of gas-liquid mass transfer resistance ratio values (0 < J < qo) which are employed in practice. The first of these effects could be analyzed by the vast experimental data obtained [3] as well as by the detailed studies on methanol-water system. As mentioned above it has been shown [16] that the Marangoni number varies only due to variations of B, at constant concmitration, mean saturation and achievement of the second critical level of mass transfer... 

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