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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 Gurthang on 11/5/2012 8:56:00 AM , Rating: 2
My only problem with Nuclear is while I agree the newer power generating reactor designs are great, pebble bed, thorium, traveling wave (if the design finally proves itself), are great. It disappoints me greatly how little progress I see getting the older reactors replaced/upgraded and how little progress I see on research to safely close the fuel cycles for the various designs. (AKA reactors designed to "burn" or reprocess waste into more easily handled products or back into fuel.) I realize some of this is due to limits we put on ourselves in NNPAs since breeders tuned to burn plutonium can just as easly be tuned to make it for example, and lets not forget the joys of running the liquid metalic sodium cooling use in most fast breeders. But this whoe bury it and pretend it all goes away thing is even dumber.


RE: .
By Vytautas on 11/5/2012 9:18:44 AM , Rating: 3
Exactly. Instead of using the newer better and more secure designs and replacing old nuclear power plants with them a lot of ignorant and scientifically illiterate people try to block the construction of new atomic powerplants forcing governments to keep the older less secure designs.


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