Scientists propose revolutionary new kind of engine for space travel

Researchers at the University of Washington have announced early findings on a potentially revolutionary new type of ‘rotating detonation engine’ which could help produce cheaper, lighter spacecraft.

A conventional rocket engine burns propellant and forces it out the back using a vast array of machinery and control nozzles to create thrust and launch the rocket skyward, without any unforeseen detours.
In the rotating detonation engine, however, the shockwave does all the work, without the need for complicated machinery in the engine

“The downside of that is that these detonations have a mind of their own. Once you detonate something, it just goes. It’s so violent.”

The researchers have since developed a mathematical model which they are poring over to begin the process of developing a functioning prototype engine which wouldn't plaster a crew against the rear of the spaceship.

Source

This sounds pretty cool. I'd love to hear what some of you aircraft guys think of this.
Typically, when we think of rocket engines, we think of something that is propelled by thrust caused by burning fuel. Researchers in the University of Washington, however, have come up with a new way of propelling aircraft or spacecraft - a "rotating detonation engine". With this design, instead of burning fuel creating thrust which propels the craft, the craft would be propelled by powerful shockwaves. This design seems, in theory, to be far more efficient; however, there's a problem: it's too powerful and unpredictable. The researchers are currently in the process of trying to design this engine to be more controllable.

a reply to: trollz

Like an Aerospike engine?

Or pulse detonation affair?

a reply to: andy06shake

Sounds like a PDE. They don't work well in atmosphere for large platforms, but should work pretty well in space. It'll be interesting to see.

Read the article. Watched the video. Have questions.

The “vast array of machinery and control nozzles” referred to typically exist only on liquid fueled rocket engines (solid-fueled rocket engines do not require their fuel to be pumped, and therefore are much simpler, mechanically) and, are used to get fuel into the combustion chamber of the rocket engine.

I do not see how this development changes any of the fuel-supply requirements, and thus “complexity” of current designs. What am I missing?

Also, from the video, it would appear that confining the detonation between the inner and outer cylinders, as described, would impart a high-speed rotational force to the exiting exhaust plume?

Would this not also induce a sort of “rifling” spin to the spacecraft attached to such an engine?

Such a “roll” would not be welcome on a manned flight, typically.

It also seems rather inefficient to lose a portion of your available “forward” thrust to a rotational momentum induced by friction between the inner and outer cylinders of the design.

I don’t get it.

a reply to: trollz

Researchers in the University of Washington, however, have come up with a new way of propelling aircraft or spacecraft - a "rotating detonation engine".

Researchers in the University of Washington did not come up with it. Neither does it make the rocket engine simpler.

In the rotating detonation engine, however, the shockwave does all the work, without the need for complicated machinery in the engine

Nope. You still need the machinery. But additionally you also have to maintain the shockwaves.

With this design, instead of burning fuel creating thrust which propels the craft, the craft would be propelled by powerful shockwaves.

No it is not propelled by shockwaves. The shockwaves purpose is to achieve a more efficient combustion allowing a higher specific impulse.

I'm going to venture a guess that it's some upgraded rocket Wankel engine.

I've always wondered if there was a way to do some kind of "slow fission" or "slow fusion" to propel a spacecraft. So rather than an atomic bomb going all kaboom and releasing all of its energy at once like a firecracker, it would slowly release its energy out a little at a time, like a pop bottle rocket. Laser ignition? You'd need a big parabolic mirror or something at the back of the spaceship to gather and focus the activity for greater thrust and to be able to steer the thing, but that wouldn't cause any big problems in space.

I think one of my favourite projects for lifting into space is the laser beam lift thing

Other than that a space elevator would actually be cheaper lol

I think once we’ve done that we’re just going to have to wait until we unlock anti gravity, of course we know it exists since we watch the stars moving further and further a way from each other

I just think we should give up on rocket engines, just seems so Stone Age now days

There are lots of efficient designs already tested and working for propulsion in space, we just don’t have that technology to take us out the solar system and elsewhere efficiently and speedily

originally posted by: moebius
a reply to: trollz

Researchers in the University of Washington, however, have come up with a new way of propelling aircraft or spacecraft - a "rotating detonation engine".

Researchers in the University of Washington did not come up with it. Neither does it make the rocket engine simpler.

In the rotating detonation engine, however, the shockwave does all the work, without the need for complicated machinery in the engine

Nope. You still need the machinery. But additionally you also have to maintain the shockwaves.

With this design, instead of burning fuel creating thrust which propels the craft, the craft would be propelled by powerful shockwaves.

No it is not propelled by shockwaves. The shockwaves purpose is to achieve a more efficient combustion allowing a higher specific impulse.

If you're going to refute the entire article, do you care to explain why we should believe you know better?

originally posted by: dogstar23
If you're going to refute the entire article, do you care to explain why we should believe you know better?

I don't recommend that you take statements from moebius, me, or anybody else as automatically true, but rather as launching points to do further research on your own, but in my experience, moebius usually knows what he's talking about, in fact I'm having a hard time thinking of a case where I found him to be wrong about something, and if that happened it was probably because he over-simplified something for the laypeople which I've done too.

RT is not a good source, so start by looking at a different source, here's one I found at Popular Mechanics which usually keeps it simple without getting overly technical:

A Rotating Detonation Engine Would Revolutionize Rocket Launches

Existing rocket engines are still internal combustion, just at a grand scale with an enormous amount of fuel. Ongoing research focuses on everything from different forms of oxidizers to 3D-printed fuel chambers, but this is still all about internal combustion—making it safer, more efficient, and most importantly, lighter weight. The Space Shuttle (RIP) weighed less than 200,000 pounds, but just the fuel weighed 20 times more than the shuttle vehicle and was used almost exclusively to get the shuttle into orbit.

A rotating detonation system promises to use less fuel and be critically lighter in weight. But taking a subsonic deflagration (traditional) reaction into supersonic detonation territory requires a repositioning of scientific thinking as well as an entirely new design for how such an engine works. Within a ring-shaped (annular) reactor, detonations trigger concentrically, and a nozzle end on the reactor creates thrust as reactants stream out of it at supersonic speeds.

So that confirms some of the things moebius said about the intention being greater fuel efficiency, and that thrust is created by the reactants streaming out the end, which confirms what moebius said that it's not the detonation that propels the craft, but the reactants.

Here's more that sounds consistent with what moebius said:

The technological basis for rotating detonation is pretty established, but a working engine that uses the technology has been more elusive.

So how is "The technological basis for rotating detonation is pretty established" if this is something brand new as the RT article suggested? That doesn't make any sense, rather "pretty established" makes it sound like it's been around a while.

I don't know when the idea first came up but it's apparently been around a while, and never implemented because though it may have more fuel efficiency in the detonation process, all the other problems have outweighed those efficiency gains and making the detonations stable has apparently been a problem.

It sounds like the researchers are trying to develop better models for the detonations to solve some of the detonation problems, but I think moebius raises valid points that just understanding the detonations better may not make it a successful design, though it could help be one step toward that.

Anyway the other sources I looked at seemed more accurate than RT, so I think you would be wiser to question RT, than to question moebius, though questioning everything is fine too. But RT isn't a great source if you want accuracy.

Sounds like Project Orion.(nuclear pulse propulsion)
en.wikipedia.org...
www.astronautix.com...