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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: Why not clean coal?
By JediJeb on 11/3/2012 11:26:03 AM , Rating: 4
Not so much wrong with hippies, but the EPA is a whole different can of worms.

I work in an Environmental Testing Laboratory, where we run analysis on water and soil to help clients with compliance with EPA regulations. In other words we are the ones who monitor what chemicals are in the drinking water and waste water and soils to ensure water is safe to drink and that companies are not polluting. While the EPA's mission may be noble, the bureaucracy that is the EPA today is the biggest waste of brain power I have ever seen. They have not begun monitoring for current risks such as newer pesticides instead we are still monitoring water for DDT which has not been used in the US for decades and other pesticides that are never used these days because others have replaced them. You could take a new pesticide and dump it right at the inlet of a drinking water plant and no one would ever know because the EPA does not regulate it and has not put out any methodologies for testing for it.

For many tests that are mandated we are forced to use 20-30 year old technology instead of modern methods of analysis simply because the EPA has not updated or approved anything new. I also once met some EPA chemists at a conference discussing new technology and found they were using it in their lab and I asked why we could not use it also, the reply way "we are the EPA, we do not have to follow the regulations but you do". In other words if you work for the EPA you can do whatever you want to report compliance data but otherwise you can be sent to jail if you do not use what is approved. We have also had discussions where our chemist have shown that an official method does not work as stated, by virtue that the chemistry just does not work, yet they will tell you if that is how it is written is it how it must be done even if it is wrong. The FDA is just as bad because it has been proven that the method they have as the approved method to test for heavy metals in foods which shows positive results by a color change, does not change color for 5 of the 10 heavy metals on the list, yet for ten years after this being proven true, it is still the only approved method to test for heavy metals in foods. That method is over 50 years old and there are much much better methods today using spectroscopy to identify each individual metal and its exact concentration yet they are still not approved.

The EPA today is more worried about politics and personal promotion than it is public safety, so don't blindly put your faith in them alone to keep the world safe from harmful chemicals in the environment. The EPA has become more of a way for the Executive branch to circumvent the Legislative branch in government than true protectors of the environment. Honestly the activist today are much better at spotting and bringing to light environmental problems than government agencies can. Our laboratory works with both sides and that seems to be the only way most of the problems will be found.


RE: Why not clean coal?
By Jeffk464 on 11/3/12, Rating: -1
RE: Why not clean coal?
By SPOOFE on 11/3/2012 5:55:59 PM , Rating: 5
"good god the level of ignorance is stunning."

... Said the world about Jeffk464.


RE: Why not clean coal?
By Reclaimer77 on 11/3/2012 5:58:36 PM , Rating: 1
quote:
good god the level of ignorance is stunning.


The level of irony of you saying this is beyond stunning..


RE: Why not clean coal?
By FITCamaro on 11/3/12, Rating: 0
RE: Why not clean coal?
By Ringold on 11/3/2012 9:24:15 PM , Rating: 2
Nancy Pelosi I think is the one you were trying to think of :P


RE: Why not clean coal?
By FITCamaro on 11/4/2012 8:48:31 PM , Rating: 2
Well we know who has multiple accounts.


RE: Why not clean coal?
By JediJeb on 11/6/2012 8:41:04 PM , Rating: 1
Well I do know scientists who are hippies or maybe it is hippies who are scientists, the two are not mutually exclusive. Of course I was not even contrasting the two, simply stating my experiences with the EPA as an organization, which is more bureaucrat now than scientist run.


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