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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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RE: .
By Kurz on 11/3/2012 9:18:04 AM , Rating: 2
http://www.nextenergynews.com/news1/next-energy-ne...

Yea they can be tiny. Depends on the output you want.


RE: .
By rvd2008 on 11/3/2012 11:50:48 AM , Rating: 2
Instead of propagating this hoax you should have spend few minutes on google. This "news" is 5-6 years old and simple reading your own link would bust it: "Toshiba expects to install the first reactor in Japan in 2008 and to begin marketing the new system in Europe and America in 2009". It is November 2012, and no installations, hmm?

Here is what you also do not know: "that's a picture of a Toshiba 10MW "4S" reactor system - 10 megawatts; it's 72 × 52.5 x 36 ft in size and it will need to be buried 100 feet underground." (more here http://www.greenlivingtips.com/blogs/185/Toshiba-n...

Nuclear subs are not small and they use complicated liquid metal cooling systems which are maintanance nightmare and costing billions. Weapon grade uranium used as fuel is another problem - they "run on highly enriched uranium, varying from from 20% U235, to the over 96% U235 found in U.S. submarines". (http://en.wikipedia.org/wiki/Nuclear_marine_propul...


RE: .
By ebakke on 11/3/2012 2:59:39 PM , Rating: 2
quote:
Nuclear subs are not small and they use complicated liquid metal cooling systems which are maintanance nightmare and costing billions.
There isn't a single reactor in the US Navy that uses liquid metal cooling. They're all PWRs.


RE: .
By rvd2008 on 11/3/2012 9:21:35 PM , Rating: 2
RE: .
By ebakke on 11/5/2012 2:46:01 AM , Rating: 2
Right, so contrary to your original claim "they" don't "use complicated liquid metal cooling systems which are maintanance nightmare and costing billions". One used that technology but was removed from service over 50 years ago!


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