The Stability of a Thermocapillary-Buoyant Flow in a Liquid Bridge with Heat Transfer Through the Interface

An experimental investigation has been performed to study a supercritical flow driven by the combined effects of buoyancy and thermocapillary forces, in a non-isothermal liquid cylindrical column heated from above (liquid bridge). The liquid zone was of 3mm in radius and 2.58mm in height made of n-decane. Changing temperature of air in the experimental chamber via controlling the temperature at its external wall, the conditions at the onset of instability of the flow, as characterized by the critical value of the imposed temperature difference, were determined for several values of the liquid volume. Performing "chaos analysis" of the obtained data, different regimes of the supercritical flow were identified. The experimental observations are supported by a computer modeling of the thermoconvective flow made for the experimental conditions neglecting deformations of the liquid-gas interface. It is shown that the spatial structure of the flow may change with external conditions in the ambient gas.