EFFECT OF AMBIENT AIR FLOW ON THERMOCAPILLARY CONVECTION IN A FULL-ZONE LIQUID BRIDGE

The effect of ambient air flow on flow-transition points in thermocapillary convection was investigated using a floating-zone method (full-zone liquid bridge) with a high Prandtl number fluid (Pr = 28.1) under normal gravity conditions. In the liquid bridge, convection changes from two-dimensional steady flow to three-dimensional unsteady flow at a flow-transition point. A pair of partition plates was employed to suppress the ambient air flow. To understand the flow and thermal fields of the ambient air, flow was visualized using smoke and temperature was measured using a thermocouple. Thermocapillary convection was stabilized by suppressing ambient air flow. The primary stabilization factor is heat transfer from the ambient air to the liquid bridge through the free surface. These results suggest that flow-transition point was controllable by modifying ambient air temperature.