Discussion:
Japanese Rocket Engine Explodes: Continuously And On Purpose
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Ted Nolan <tednolan>
2021-09-07 03:02:22 UTC
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https://hackaday.com/2021/09/02/japanese-rocket-engine-explodes-continuously-and-on-purpose/

Sounds interesting, if finicky:

Humans love combusting fuels in order to do useful work.
Thus far in our history, whether we look at steam engines,
gasoline engines, or even rocket engines, all these
technologies have had one thing in common: they all rely
on fuel that burns in a deflagration. It's the easily
controlled manner of slow combustion that we're all familiar
with since we started sitting around campfires.

However, there are potential efficiency gains to be had by
combusting fuel in a detonation instead. This is where the
combustion creates a shock wave that travels faster than
the speed of sound that rapidly propagates the detonation
reaction further, and comes with a huge pressure increase
to boot. The key advantage of burning fuel in this manner
is that there is more energy to be gained from that huge
pressure increase. Thus, by releasing more energy from the
same amount of fuel, engines operating on a detonation-based
process could theoretically be more energy efficient.

There are several issues with operating an engine on a
detonation-based cycle, however. It can be difficult to
sustain a continuous detonation reaction. Additionally,
large spikes in temperature and pressure from the detonation
process and the associated shockwaves can easily damage or
destroy parts made of even very tough materials. Thus far,
engineers in many fields have struggled to tame and control
detonation processes to the point where they can be used
successfully.

The rotating detonation engine consists of a combustion
chamber that has a annular, ring-type construction. In this
ring, fuel and oxidizer is injected, and ignited in such a
way to detonate the mixture. The aim is for the shockwave
of this detonation to travel around the ring-shaped combustion
chamber causing further detonations as it goes in a continuous
cycle.
--
columbiaclosings.com
What's not in Columbia anymore..
pete...@gmail.com
2021-09-07 03:25:52 UTC
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Post by Ted Nolan <tednolan>
https://hackaday.com/2021/09/02/japanese-rocket-engine-explodes-continuously-and-on-purpose/
Humans love combusting fuels in order to do useful work.
Thus far in our history, whether we look at steam engines,
gasoline engines, or even rocket engines, all these
technologies have had one thing in common: they all rely
on fuel that burns in a deflagration. It's the easily
controlled manner of slow combustion that we're all familiar
with since we started sitting around campfires.
However, there are potential efficiency gains to be had by
combusting fuel in a detonation instead. This is where the
combustion creates a shock wave that travels faster than
the speed of sound that rapidly propagates the detonation
reaction further, and comes with a huge pressure increase
to boot. The key advantage of burning fuel in this manner
is that there is more energy to be gained from that huge
pressure increase. Thus, by releasing more energy from the
same amount of fuel, engines operating on a detonation-based
process could theoretically be more energy efficient.
There are several issues with operating an engine on a
detonation-based cycle, however. It can be difficult to
sustain a continuous detonation reaction. Additionally,
large spikes in temperature and pressure from the detonation
process and the associated shockwaves can easily damage or
destroy parts made of even very tough materials. Thus far,
engineers in many fields have struggled to tame and control
detonation processes to the point where they can be used
successfully.
The rotating detonation engine consists of a combustion
chamber that has a annular, ring-type construction. In this
ring, fuel and oxidizer is injected, and ignited in such a
way to detonate the mixture. The aim is for the shockwave
of this detonation to travel around the ring-shaped combustion
chamber causing further detonations as it goes in a continuous
cycle.
I think I mentioned these here a few months ago. Here's a nice video
explanation.



One drawback is that they are insanely loud.

Pt
Dimensional Traveler
2021-09-07 04:27:04 UTC
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Permalink
Post by ***@gmail.com
Post by Ted Nolan <tednolan>
https://hackaday.com/2021/09/02/japanese-rocket-engine-explodes-continuously-and-on-purpose/
Humans love combusting fuels in order to do useful work.
Thus far in our history, whether we look at steam engines,
gasoline engines, or even rocket engines, all these
technologies have had one thing in common: they all rely
on fuel that burns in a deflagration. It's the easily
controlled manner of slow combustion that we're all familiar
with since we started sitting around campfires.
However, there are potential efficiency gains to be had by
combusting fuel in a detonation instead. This is where the
combustion creates a shock wave that travels faster than
the speed of sound that rapidly propagates the detonation
reaction further, and comes with a huge pressure increase
to boot. The key advantage of burning fuel in this manner
is that there is more energy to be gained from that huge
pressure increase. Thus, by releasing more energy from the
same amount of fuel, engines operating on a detonation-based
process could theoretically be more energy efficient.
There are several issues with operating an engine on a
detonation-based cycle, however. It can be difficult to
sustain a continuous detonation reaction. Additionally,
large spikes in temperature and pressure from the detonation
process and the associated shockwaves can easily damage or
destroy parts made of even very tough materials. Thus far,
engineers in many fields have struggled to tame and control
detonation processes to the point where they can be used
successfully.
The rotating detonation engine consists of a combustion
chamber that has a annular, ring-type construction. In this
ring, fuel and oxidizer is injected, and ignited in such a
way to detonate the mixture. The aim is for the shockwave
of this detonation to travel around the ring-shaped combustion
chamber causing further detonations as it goes in a continuous
cycle.
I think I mentioned these here a few months ago. Here's a nice video
explanation.
http://youtu.be/rG_Eh0J_4_s
One drawback is that they are insanely loud.
In space, no one can hear your engine explode.
--
I've done good in this world. Now I'm tired and just want to be a cranky
dirty old man.
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