This phenomenon, called cavitation, can be used to clean jewelry and disintegrate kidney stones but is better known for damage. Though Leonhard Euler described cavitation in 1754, the phenomenon made its big engineering impression in 1893 when it caused the failure of a propeller on the world's fastest ship at the time, Great Britain's HMS Daring. In modern times, degraded performance is the typical consequence, as maintenance crews usually discover and replace damaged components before they fail.
Since then, cavitation has been studied extensively, though primarily related to expensive issues like ships and ship propellers in open water.
The first detailed results of experiments aimed at preventing cavitation damage in jet fuel pumps showed great differences in cavitation behavior between water and JP-8 jet fuel, which is a complex mixture of more than 228 hydrocarbons and additives, each with its own fluid properties.
It's much more difficult to model cavitation in pumps than in open water because the fluid typically has a turbulent journey with accelerated flows though small channels, orifices, and spinning discs. With so many constituents, jet fuel is also a numerical model's nightmare. Its properties can even change with storage conditions and is often contaminated with microparticles that can promote cavitation.
The researchers say they work provides jet-fuel pump designers with the first realistic data that they can use in their computer models to make better predictions of vulnerable locations in their pumps and systems where cavitation bubbles may be created and collapse.
"Improved jet-fuel pumps are needed particularly for military aircraft being designed to fly at higher altitudes and in other demanding environments," said Notre Dame professor Patrick Dunn, one of the study authors. "But manufacturers still rely heavily upon trial-and-error in design. If they were confident that a computer-designed pump would work as predicted, new pumps could be lighter, more efficient and have longer lifetimes."
Citation: Patrick F. Dunn, Flint O. Thomas, Michael P. Davis, and Irina E. Dorofeeva, 'Experimental characterization of aviation-fuel cavitation', Phys. Fluids 22, 117102 (2010); doi:10.1063/1.3490051
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