09. Heat and Mass Transfer

Thermal Marangoni convection driven by temperature difference on the gas/liquid surface has been of interest for researchers due to its rich dynamical features and also for its wide existence in nature and industrial processes. However, most studies have focused on thermal Marangoni convection with the case of single free surface, Marangoni convection with two free surface is seldomly considered while the two free surfaces system is a potential way to realize a new kind of crystallization process of materials, to avoid the liquid being contaminated by impurities supplied from the solid plate. Results show that a new phenomenon would be observed compared with the case of single free surface. The flow is steady at a relatively small Marangoni number. A different flow structure in the rectangular hole appears, the fluid on two free surfaces is driven from the hot wall to the cold wall due to the thermal Marangoni effect, and then returns inside the liquid layer towards the hot wall. For the oscillatory flow, the wave patterns of temperature fluctuations are highly depended on the effect of thermal Marangoni flow, and standing-wave type instability would be observed with the enhancement of Marangoni force, the disturbance energy concerning the case of two free surface is much stronger and the temperature fluctuation is always larger than that of the case of single free surface.