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Interesting. As I understand it, deflagration is usually used in rocket engines because detonation is hard to control, but they’ve managed to control it using

Interesting. As I understand it, deflagration is usually used in rocket engines because detonation is hard to control, but they’ve managed to control it using very precise engineering.

wtvanhest 7y ago
Yeah, I wasn’t expecting much, but it sounds like a real potential breakthrough. I’d love to see someone with experience in the industry comment
- boredgamer2 7y ago
  There is a comment at the bottom of the article from an expert in the Air Force: > William Hargus, lead of the Air Force Research Laboratory's Rotating Detonation Rocket Engine Program, is a co-author of the study and began working with Ahmed on the project last summer. > "As an advanced propulsion spectroscopist, I recognized some of the unique challenges in the observation of hydrogen-detonation structures," Hargus said. "After consulting with Professor Ahmed, we were able to formulate a slightly modified experimental apparatus that significantly increased the relevant signal strength." > "These research results already are having repercussions across the international research community," Hargus said. "Several projects are now re-examining hydrogen detonation combustion within rotating detonation rocket engines because of these results. I am very proud to be associated with this high-quality research."
loeg 7y ago
I guess one question is, can they maintain that precise control over a long enough period of time, without the explosions degrading the injection apertures, to really use the technology.
- sandworm101 7y ago
  At the fuel flows they are using, the explosions aren't that much of an issue. These look like wisps of hydrogen and oxygen in a vacuum chamber, not a big jet of fire steaming out of a nozzle. The detonation wave doesn't look like it is contacting much of anything. They have a sustained rotating ring, a detonation chasing itself around a circle. That's great, its more efficient, but it is a long way from a working engine. They need a properly shaped chamber, a nozzle, and a few other things before they can test for the expected increase in ISP.
seiferteric 7y ago
Sounds similar to the jet version, pulse detonation engines (PDE) https://en.wikipedia.org/wiki/Pulse_detonation_engine https://en.wikipedia.org/wiki/Pulse_detonation_engine
- burfog 7y ago
  Well, minus the pulse, which would be great for air-breathing engines too. If you made a ring of pulse-detonation engines that fired one after another in sequence, you'd almost have such a thing. Connect the tubes side-to-side if you can, merging them into a coaxial detonation chamber with a helical detonation wave that rotates. (looking almost like an annular aerospike engine but leaving a helical exhaust trail) You probably need to run with more than one helix in the engine to avoid disastrous vibration.

Interesting. As I understand it, deflagration is usually used in rocket engines because detonation is hard to control, but they’ve managed to control it using very precise engineering.

wtvanhest 7y ago

Yeah, I wasn’t expecting much, but it sounds like a real potential breakthrough. I’d love to see someone with experience in the industry comment

boredgamer2 7y ago
There is a comment at the bottom of the article from an expert in the Air Force: > William Hargus, lead of the Air Force Research Laboratory's Rotating Detonation Rocket Engine Program, is a co-author of the study and began working with Ahmed on the project last summer. > "As an advanced propulsion spectroscopist, I recognized some of the unique challenges in the observation of hydrogen-detonation structures," Hargus said. "After consulting with Professor Ahmed, we were able to formulate a slightly modified experimental apparatus that significantly increased the relevant signal strength." > "These research results already are having repercussions across the international research community," Hargus said. "Several projects are now re-examining hydrogen detonation combustion within rotating detonation rocket engines because of these results. I am very proud to be associated with this high-quality research."

loeg 7y ago

I guess one question is, can they maintain that precise control over a long enough period of time, without the explosions degrading the injection apertures, to really use the technology.

sandworm101 7y ago
At the fuel flows they are using, the explosions aren't that much of an issue. These look like wisps of hydrogen and oxygen in a vacuum chamber, not a big jet of fire steaming out of a nozzle. The detonation wave doesn't look like it is contacting much of anything. They have a sustained rotating ring, a detonation chasing itself around a circle. That's great, its more efficient, but it is a long way from a working engine. They need a properly shaped chamber, a nozzle, and a few other things before they can test for the expected increase in ISP.

seiferteric 7y ago

Sounds similar to the jet version, pulse detonation engines (PDE) https://en.wikipedia.org/wiki/Pulse_detonation_engine https://en.wikipedia.org/wiki/Pulse_detonation_engine

burfog 7y ago
Well, minus the pulse, which would be great for air-breathing engines too. If you made a ring of pulse-detonation engines that fired one after another in sequence, you'd almost have such a thing. Connect the tubes side-to-side if you can, merging them into a coaxial detonation chamber with a helical detonation wave that rotates. (looking almost like an annular aerospike engine but leaving a helical exhaust trail) You probably need to run with more than one helix in the engine to avoid disastrous vibration.