Abstract
In the present study we observed Marangoni convection at the vapor-liquid interface of alcohol aqueous solution. It was driven by the surface tension variation caused by temperature and concentration gradients along the bubble surface. Vochten and Petre found that surface tension in aqueous solution of higher alcohol such as butanol aqueous solution has a minimum in the surface tension temperature curves. In higher temperature, the surface tension increased as the temperature increased. We used PIV measurement for the observation of the convection about 1-butanol aqueous solution, ethanol aqueous solution and pure water. In addition, we compared the experiment with CFD simulations. When we kept the heated surface at the boiling point temperature approximately, it was found from this study that the direction of Marangoni convection in alcohol solution was toward the heated surface and it occurred in the opposite direction in the pure water, because pure water does not have concentration gradient. Moreover the velocity of 1-butanol aqueous solution was faster than ethanol aqueous solution. Especially, the velocity of 1-butanol aqueous solution (7.15wt%, 3.0wt%) was 4 times higher than ethanol aqueous solution. We supposed that both the temperature and the concentration gradients acted on the convection effectively.
