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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 Reclaimer77 on 11/3/2012 5:09:52 PM , Rating: 2
First off V-Money, thank you for your service to our country, sir.

Secondly, isn't most of what you're saying true because of budget cutbacks and the fact that we've severely halted most next-generation power-plant design projects?

It seems to me that if we had kept at it, we would have safer more compact designs today that could be deployed in a wide range of surface ship designs. But I'm just a layman without your real-world experience, of course.

I agree we can't realistically have a 100% nuclear powered surface Navy, but I would think that anything from cruiser-sized on up would benefit greatly from it.


RE: .
By V-Money on 11/5/2012 12:35:30 PM , Rating: 2
Your welcome, and I highly recommend to everyone to serve at least a 2 year enlistment, even if you are against combat you can always play a support role. It really does make a positive change in most people.

As for designs, we use older designs because they are tried and true. The new Virginia class is a huge step up from the L.A. Class in terms of technology and design, and it can be operated with fewer people. The problem that arises is that the Nuclear Navy can't risk having any type of accident, so we limit pushing new technology until it has been proven and train our crews to handle any (likely and unlikely) scenario.

As for the smaller reactors, I once served onboard the submarine NR-1 (look it up, its a very unique vessel that almost nobody knows about) which had a small, compact reactor and design that could work in any ship. This was made possible by only allowing the most highly qualified nukes to operate it.

To put it simply though, it is possible. We already have usable designs since we have had nuclear cruisers in the past, they were decommissioned though because it was too expensive to run them. We could easily get the costs down if it weren't for public paranoia because we go overboard on making sure nothing happens to any of the reactors. If you could only see the designs we use now they are already extremely safe and only the absolutely worst worst case scenarios could cause any harm, and even then it wouldn't be as bad as people fear.

Unfortunately though people like to live in scared little worlds of their own where they mistakenly believe anything told to them. Instead of trying to understand new technology, they just denounce it as evil (nuclear power) while saying they support non-viable alternatives (wind/solar power) while in reality their own excessive usage of energy forces us to rely on the worst possible alternatives (coal/oil power).


"It's okay. The scenarios aren't that clear. But it's good looking. [Steve Jobs] does good design, and [the iPad] is absolutely a good example of that." -- Bill Gates on the Apple iPad

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