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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 V-Money on 11/3/2012 3:21:01 PM , Rating: 2
quote:
if the reactor takes a direct hit from a anti ship missile no radiation is going to leak out.


There are so many things wrong with this statement (such as a direct hit, this isn't the deathstar where you can shoot inside a vent to score a direct hit on a reactor). I would be glad to discuss this issue with you in a civilized manner if you at the very least look up the difference between radiation and contamination (and maybe look at the definition of radiation).

I've worked for years in close quarters to a live nuclear reactor while onboard submarines, and I have no problems discussing nuclear power. I will not waste my time with people who are so closed minded that they will not listen to facts and only use keywords and catch phrases they heard from others as arguments (A.K.A. Meltdown, supercritical, Fukushima, etc.)


RE: .
By Jeffk464 on 11/3/12, Rating: -1
RE: .
By Vytautas on 11/3/2012 4:35:44 PM , Rating: 4
That's the crazy thing. How many died in Fukushima? 2 direct deaths and an estimated 28 (from 3 to 245) indirect ones due to cancer. How many died in the Bangiao Dam accident? 26 thousand! In general hydroelectric power alone has caused about 171 thousand deaths worldwide. Compare that to nuclear. Again fear mongering about the unknown dangers of the invisible radiation is a symptom and example of human stupidity and lack of education rather than a real risk.
Look at the following comparisons of death tolls by power generated:
http://www.the9billion.com/2011/03/24/death-rate-f...
or
http://www.forbes.com/sites/jamesconca/2012/06/10/...

As you can see the difference is not even in the same order of magnitude with nuclear being the safest power generation technology in history.


RE: .
By Vytautas on 11/3/2012 4:40:22 PM , Rating: 2
Some additional statistics including other power source types:
Coal (elect, heat,cook –world avg) 100 (26% of world energy, 50% of electricity)
Coal electricity – world avg 60 (26% of world energy, 50% of electricity)
Coal (elect,heat,cook)– China 170
Coal electricity- China 90
Coal – USA 15
Oil 36 (36% of world energy)
Natural Gas 4 (21% of world energy)
Biofuel/Biomass 12
Peat 12
Solar (rooftop) 0.44 (0.2% of world energy for all solar)
Wind 0.15 (1.6% of world energy)
Hydro 0.10 (europe death rate, 2.2% of world energy)
Hydro - world including Banqiao) 1.4 (about 2500 TWh/yr and 171,000 Banqiao dead)
Nuclear 0.04 (5.9% of world energy)


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.


RE: .
By Reclaimer77 on 11/3/2012 4:57:44 PM , Rating: 1
How about you do the adults in the room a favor, and go to bed without supper Jeffk?

Seriously, it's hard to not "resort" to name calling when someone says the most retarded things ever about a given subject.


RE: .
By Solandri on 11/3/2012 5:46:49 PM , Rating: 5
quote:
Why do you think the public is so nervous about nuclear power? Every time they start to become convinced that its safe there is another nuclear accident.

The "problem" with nuclear power is that it's an incredibly concentrated power source. A single nuclear reactor replaces about 7 coal plants, or about 5,000-15,000 wind turbines. And a nuclear plant typically has 2-4 reactors.

But when it comes to the consequences of accidents, people think in terms of 1 nuclear reactor = 1 coal plant = 1 wind turbine. Just like people equate 1 airplane crash = 1 car crash and are afraid to fly even though they're more likely to die while riding a car.

If you normalize for the amount of power generated, nuclear turns out to be the safest power source man has ever invented. Yes a single wind turbine is safer than a nuclear reactor. But the 10,000 wind turbines needed to equal the nuclear reactor's power output turn out to be cumulatively more dangerous.

The only other power source which is comparable to nuclear in terms of energy density is hydro. A hydroelectric dam on a large river has a generating capacity similar to or even exceeding a nuclear plant with multiple reactors. This is the reason the worst power generation accident in history (est. 170,000 killed, 6 million buildings destroyed, 11 million people evacuated) was the failure of series of hydroelectric dams. But water is something we deal with every day, while nuclear decay is just an abstract concept. So people fear nuclear while they have no problem with the more dangerous hydro.


RE: .
By Jeffk464 on 11/4/12, Rating: -1
RE: .
By MadMan007 on 11/4/2012 11:15:17 AM , Rating: 2
When the public is stupid and wrong, what they think should matter a lot less.


RE: .
By bodar on 11/5/2012 4:34:47 AM , Rating: 2
This is what happens when you don't properly educate kids, like say, in critical thinking skills or science.


RE: .
By Vytautas on 11/5/2012 12:02:25 AM , Rating: 2
I suppose it´s not a very nice feeling when other find you ignorant or stupid. You don´t seem a bad person per se, just as previously said ignorant. Yes, there has been some backslash due to the events in Fukushima, but guess what, atomic power plants are still being built and new plants are being planned even now. For example the case of Germany and France. Germany has decided to close their atomic powerplants and import the electricity from other countries, mainly France which has a surplus due to.... "atomic power". : ) : ) In other words, nothing has really changed just that the german people will have negative economic repercussions for this decision, while the french will certainly benefit. Yes, it´s true that for now there is a reduced interest in atomic powerplants, but even so there is a backlog of five to ten years if not more for new reactor housings and such (due to the limited amount of manufacturing capacity).

In short. The common person is pretty ignorant of all scientific matters and very inclined to believe all kinds of missinformation and fearmongering lies. Also that person is also very inclined to fear the unknown. But the truth is that if we allow our decisions to be determined by this common stupidity denominator the countries of the world will suffer the economical and ecological consequences.

Whatever you believe, know this: atomic power is the cleanest and most economically and ecologically sensible energy generation technology humanity has developed till now. If you prefer dying of cancer due to the fumes of coal or oil power plants be my guest. If you think wind and solar power would be enough you have deluded yourself. The inherent instability of such power sources allows it to provide up to 10-15% of the total energy generation capacity. Meaning it´s got its´ place but cannot be the main source of energy for humanity unless you are happy having brownouts all the time or having each family be forced to invest tens of thousands of dollars in battery backups every five years. Not speaking about industry which in some cases MUST have an uninterrupted supply of electricity due to the production processes involved. Fossil fuels (coal, oil or gas) are a very dirty source of energy and one which will get more expensive each day.

There is a lot more information about this subject I could give you. If you are really interested to learn about this, let me know I will gladly help you.


RE: .
By JediJeb on 11/6/2012 8:53:18 PM , Rating: 2
quote:
Why do you think the public is so nervous about nuclear power?


Why is the public nervous about nuclear power? Because the voices of idiots are normally much louder than the voices of the wise.


"I f***ing cannot play Halo 2 multiplayer. I cannot do it." -- Bungie Technical Lead Chris Butcher

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