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NRL's model of a Rotating Detonation Engine  (Source: nrl.navy.mil)
Currently, the Navy has 129 ships with 430 gas-turbine engines that burn $2 billion of fuel annually

The U.S. Navy is working on new technology for its gas-turbine engines in order to decrease fuel consumption without sacrificing performance.

The answer, according to the Naval Research Laboratory (NRL), is equipping current gas-turbine engines with Rotating Detonation Engine (RDE) technology. These engines could not only efficiently provide propulsion for Navy planes and ships, but also create electricity for an all-electric propulsion system.

The Navy currently uses gas-turbine engines that are based on the Brayton thermodynamic cycle, where air is compressed, combined with fuel, combusted at a constant pressure and expanded. This allows for propulsion or generating electricity, just like the RDEs. However, the Brayton cycle is less efficient than the detonation cycle.

Dr. Kazhikathra Kailasanath, head of NRL's Laboratories for Computational Physics and Fluid Dynamics, noted the following in a 2011 paper for the NRL Review:

The challenge with detonation engines is realizing the efficiency of the detonation cycle. Concepts such as oblique detonation-wave engines have failed to be able to recover the efficiency of this detonation cycle, because much of the energy of the inflow is bound up in kinetic energy, which does not increase the pressure and thus does not improve the efficiency. Pulse detonation engines have taken a different approach by creating an unsteady process that removes the requirement of having high velocity inflow. This creates a whole new set of issues, such as rapid initiation of detonations and the requirement of efficient detonators.

The rotating detonation engine takes a different approach toward realizing the efficiency of the detonation cycle. By allowing the detonation to propagate azimuthally around an annular combustion chamber, the kinetic energy of the inflow can be held to a relatively low value, and thus the RDE can use most of the compression for gains in efficiency, while the flow field matches the steady detonation cycle closely.

Currently, the Navy has 129 ships with 430 gas-turbine engines that burn $2 billion of fuel annually. By equipping engines with RDE technology, power could be increased by 10 percent while fuel consumption would decrease by 25 percent. The Navy could also save $300-$400 million annually.

Source: U.S. Navy



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wow is "safe" relative?
By bebimbap on 11/3/2012 6:12:30 PM , Rating: 1
Having read most of the replies, wow.

coal is probably the most environmentally devastating fossil fuel of them all.
first the MINING of it, people die all the time in coal operations. Even surface mining destroys any kind of ecosystem the area once had. Oil could but Coal mining definitely destroys it. and lives? well...
http://www.huffingtonpost.com/2010/12/30/us-coal-m...
That's just from mining. even getting it ready for transport, is very hazardous to workers. There are many "Rat hole > bulldozer" stories.
Then there is the burning of it. the ash from coal burning is very carcinogenic, and radioactive. http://www.scientificamerican.com/article.cfm?id=c...

The issue about warships is they not only require kinetic energy, they also require incredible amounts of electricity. So you require a way to do both or switch quickly between the two. Then you also have to be able to use your energy without seeing a huge smoke stack from 200 miles away. and for this application turbines are great esp paired with high energy density fuels.

any technology is dangerous when used irresponsibly such as Fukushima (nuclear), Kingston Fossil Plant(coal), Buffalo Creek Flood (coal), Martin County sludge spill (coal), Chernobyl (nuclear), and even wind turbines !!! http://www.abcbirds.org/newsandreports/releases/11... but responsible planning and building could have prevented all of these disasters.

The only thing that's really dangerous is greed since it seems to be a precursor to every disaster, and trumps responsibility every time.




RE: wow is "safe" relative?
By MadMan007 on 11/4/2012 11:08:40 AM , Rating: 1
What, you mean greed ISN'T good?!


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