On the induction criterion of the Marangoni convection at the gas/liquid interface

Some spreading solutes were found to be effective in enhancing the absorption rate by provoking interfacial turbulence at the gas-liquid surface. In this work, the induction criterion of the Marangoni convection is explored experimentally and theoretically by using aqueous solutions of normal alcohols and surfactants as spreading liquids. The experimental results show that aqueous solutions of methanol, ethanol, n-propanol, n-butanol, and n-pentanol may induce significant interfacial turbulence, and, on the other hand, aqueous solutions of n-hexanol, n-octanol, SDS, DTMAC, and Triton X-100 do not provoke noticeable interfacial turbulence. A dimensionless Marangoni number, Ma, based an film thickness delta is satisfactorily developed to evaluate the potentiality of a spreading Liquid to produce interfacial turbulence. The critical Marangoni number, Ma, c, for the occurrence of the Marangoni convection is also determined.