NASA astronaut Jeffrey Williams with the Capillary Flow Experiment (CFE), used to study the behaviour of liquids in capillaries in reduced gravity conditions on board the ISS.
This study is of great importance for space missions because the results could affect the construction of tanks and cooling systems, to name one example. Systematic handling of liquids is also relevant to safety. This is true for fuel and for water and liquefied gases.
A promising and technically elegant solution is the use of open-sided conduits, known as capillary channels, through which liquid flows. Researchers have constructed mathematical models of the forces that act on the liquids using fluid mechanics. These theoretical calculations can only be confirmed or disproved by microgravity experiments.