For more than 250 years, researchers have known that under certain conditions vapor bubbles can form in fluids moving swiftly over a surface. These bubbles soon collapse with such great force that they can poke holes in steel and damage objects such as ship propellers, turbine blades, nozzles and pump impellers.
Scientists have conducted extensive research for decades to try to understand this phenomenon -- called cavitation. But most experiments to date have been related to open-water objects like ship propellers.
Now a group led by Notre Dame professors Patrick Dunn and Flint Thomas has published the first detailed results of experiments aimed at preventing cavitation damage in jet fuel pumps, which are essential components in modern aircraft. Appearing in journal Physics of Fluids, which is published by the American Institute of Physics, the results 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.
While it can be used to clean jewelry and disintegrate kidney stones, cavitation is usually considered to be highly detrimental and to be avoided. It was first described scientifically by Leonhard Euler in 1754, but the phenomenon made its initial impression with engineers 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.
“Improved jet-fuel pumps are needed particularly for military aircraft being designed to fly at higher altitudes and in other demanding environments,” Dunn said. “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.”
The Notre Dame research 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.
It’s much more difficult to model cavitation in pumps than in open water, Dunn added, 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 computer modeler’s nightmare. Its properties can even change with storage conditions and is often contaminated with microparticles that can promote cavitation.
The article, "Experimental Characterization of Aviation-Fuel Cavitation" by Patrick F. Dunn, Flint O. Thomas, Michael P. Davis and Irina E. Dorofeeva appears in the journal Physics of Fluids. See: http://link.aip.org/link/phfle6/v22/i11/p117102/s1
Journalists may request a free PDF of this article by contacting email@example.com
This research was funded by Honeywell Corp.PHYSICS OF FLUIDS
Jason Socrates Bardi | Newswise Science News
NASA's James Webb Space Telescope completes final cryogenic testing
21.11.2017 | NASA/Goddard Space Flight Center
Previous evidence of water on mars now identified as grainflows
21.11.2017 | US Geological Survey
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Life Sciences
22.11.2017 | Materials Sciences
22.11.2017 | Life Sciences