Thermocapillary flow on a gas-liquid surface under normal and reduced gravity

The aim of the present work is the study of the thermocapillary flow phenomenon at 1-g, μ-g conditions and the transition between 1-g and μ-g. The experimental results were observed with a novel high speed imaging system using a combination of a monochrome high speed CCD camera and a liquid crystal tunable filter. The flow velocity and the temperature patterns could be measured simultaneously from the seeded thermochromic liquid crystals, which change colour depending on their temperature. We investigated the thermocapillary flow with an experimental setup, where a bubble is positioned in a liquid matrix under a heated wall. The µ-g experiments were conducted in the drop tower of the ZARM-Institute of the University of Bremen. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)