Temperature fields in a liquid due to the thermocapillary motion of bubbles and drops

Experiments were performed on the motion of isolated air bubbles and drops of Fluorinert FC-75 moving in a Dow-Coming silicone oil under the action of an applied temperature gradient in a reduced gravity environment aboard the Space Shuttle in orbit. The disturbance of the imposed temperature field due to the motion of the objects was studied optically using a shearing interferometer with a Wollaston prism and the results of aa typical bubble run were compared with theoretical predictions. Also, the liquid velocity field surrounding the bubbles and drops has been qualitatively investigated in a few runs by the observation of tracer particles dispersed in the continuous phase fluid. The measurement techniques are described, and the results for the temperature and flow fields are presented and discussed.