Microgravity experimental of bubbles thermocapillary migration and interaction

Space experiment on bubble thermocapillary migration was performed on board the Chinese 22nd recoverable satellite in 2005. Some results on bubble interaction and bubble coalescence are presented in the paper. A bubble or drop will move to hot side when placed in another fluid and subjected to a temperature gradient in microgravity. If there are multi-bubbles or multi-drops in the fluid, it is possible that we observer to chase, hit, surpass or coalescence of the bubbles or drops etc. In the space experiment, a cubic test cell was designed. 5cSt silicone oil was used as matrix phase. Two independence sets of injected liquid facility are installed in the experimental box. The real bubble thermocapillary migrations experiment were done after 100min from the power on of temperature controllers, in order to keep a steady temperature gradient field in the test cell. The recorded temperature data, video image of bubble migration in the experiment and the test facility were recovered along with the recoverable cabin of satellite. The bobble migration velocities are obtained by measuring the bobble's tracks according to recorded image. Bubble coalescences are also observed through the bubbles staying at the upper side of the test cell in the experiment. Copyright IAF/IAA. All rights reserved