GROUND EXPERIMENTS OF BOUYANT THERMOCAPILLARY CONVECTION OF LARGE SCALE LIQUID BRIDGE WITH LARGE PRANDTL NUMBER

Thermocapillary-driven convection in a large scale liquid bridge was investigated by ground experiments in this paper. We used 2 cst silicone oil (Pr=28.571), observed the onset of liquid bridge with different aspect ratios (A=l/d) and volumes, analyzed the transformation of temperature oscillation frequency and phase, discussed the problems of hydrothermal waves. The column diameter of liquid bridge was 20mm. Due to the limit by gravity, we constructed the bridge with 3-4.25mm height. With the help of five azimuthal thermocouples inserted in the bridge interior, we discovered that temperature oscillation in flow field occurs at the same time; bridges with different aspect ratios and volumes have different flow modes, and with the increase of temperature difference, the frequency increases approximately linearly, and oscillation phase of each temperature oscillation curve continuously changes. Bridges with different aspect ratios have different ways to chaos.