Behaviour of Water in Jet Fuel in a Simulated Fuel Tank 2011-01-2794

Experimental studies were performed to gain a better understanding of the behaviour of water in jet fuel at low temperatures. The transition of water in fuel from dissolved water to free water, and its subsequent precipitation behaviour when the fuel was cooled down, were investigated using a 20 litre glass-windowed aluminium tank. The effects of cooled internal surfaces were explored with chilled plates at the top and bottom of the aluminium tank. The tank was fitted with an array of thermocouples, which allowed horizontal and vertical temperature profiles to be measured. A laser visualisation system incorporating image processing software was used to capture images inside the simulated tank without interfering with the convective flow of the fuel.

Fuel will precipitate any excess dissolved water when cooled below the saturation temperature. The excess water may then appear in the form of fine water droplets or ice particles as a fine cloud (fog). The observed fog regimes were closely related to the cooling modes. Water/ice precipitation on a subcooled surface was also studied. The results show that water/ice deposition on the subcooled surface by the Bergeron process.