The Briefing Room
General Category => Science, Technology and Knowledge => Space => Topic started by: Elderberry on January 29, 2023, 02:53:38 am
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NASA by Ray Osorio 1/25/2023
https://www.nasa.gov/centers/marshall/feature/nasa-validates-revolutionary-propulsion-design-for-deep-space-missions (https://www.nasa.gov/centers/marshall/feature/nasa-validates-revolutionary-propulsion-design-for-deep-space-missions)
As NASA takes its first steps toward establishing a long-term presence on the Moon’s surface, a team of propulsion development engineers at NASA have developed and tested NASA’s first full-scale rotating detonation rocket engine, or RDRE, an advanced rocket engine design that could significantly change how future propulsion systems are built.
(https://www.nasa.gov/sites/default/files/styles/full_width/public/thumbnails/image/2022-08-fulltest.png?itok=aIv85GZO)
Rotating detonation rocket engine, or RDRE hot fire test at Marshall Space Flight Center.
The RDRE differs from a traditional rocket engine by generating thrust using a supersonic combustion phenomenon known as a detonation. This design produces more power while using less fuel than today’s propulsion systems and has the potential to power both human landers and interplanetary vehicles to deep space destinations, such as the Moon and Mars.
Engineers at NASA’s Marshall Space Flight Center in Huntsville, Alabama, and primary collaborator IN Space LLC, located in West Lafayette, Indiana, are confirming data from RDRE hot fire tests conducted in 2022 at Marshall’s East Test Area. The engine was fired over a dozen times, totaling nearly 10 minutes in duration.
https://www.youtube.com/watch?v=jBWUim-rppQ (https://www.youtube.com/watch?v=jBWUim-rppQ)
The RDRE achieved its primary test objective by demonstrating that its hardware – made from novel additive manufacturing, or 3D printing, designs and processes – could operate for long durations while withstanding the extreme heat and pressure environments generated by detonations. While operating at full throttle, the RDRE produced over 4,000 pounds of thrust for nearly a minute at an average chamber pressure of 622 pounds per square inch, the highest pressure rating for this design on record.
The RDRE incorporates the NASA-developed copper-alloy GRCop-42 with the powder bed fusion additive manufacturing process, allowing the engine to operate under extreme conditions for longer durations without overheating.
Additional milestones achieved during the test include the successful performance of both deep throttling and internal ignition. This successful demonstration brings the technology closer to being used with future flight vehicles, enabling NASA and commercial space to move more payload and mass to deep space destinations, an essential component to making space exploration more sustainable. Because of NASA’s recent success with the RDRE, follow-on work is being conducted by NASA engineers to develop a fully reusable 10,000-pound class RDRE to identify performance benefits over traditional liquid rocket engines.
RDRE is managed and funded by the Game Changing Development Program in NASA’s Space Technology Mission Directorate.
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So anybody catch the increase in efficiency or thrust per given unit of measurement? Are we talking 2 or 50%?
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So anybody catch the increase in efficiency or thrust per given unit of measurement? Are we talking 2 or 50%?
Not enough data available online yet.
https://www.reddit.com/r/AerospaceEngineering/comments/10m1w0c/what_sort_of_specific_impulse_could_a_rotating/
What sort of specific impulse could a Rotating Detonation Rocket Engine (RDRE) achieve?
coldfusion051
· 2 days ago
As a quick approximation of ideal performance, the specific impulse can be calculated the same as a constant pressure device:
Isp = sqrt( 2*c_p*T_c*( 1-(p_e/p_c)(k-1)/k ) )
The subtlety comes in which T_c and p_c to use. RDEs operate on an unsteady thermodynamic cycle, so there isn't a single T_c and p_c that you could theoretically measure and plug into the equation. However, keeping with the quick approximation approach, T_c can be approximated as the chamber temperature from a CEA rocket calculation (there are thermodynamic reasons for this, but I won't get into them here). p_c will be some multiple of the propellant manifold/supply pressure - greater than if it produces a "pressure gain", and less than if it's a low-performance RDE.
For the highest theoretical performance, p_c could be as much as twice the propellant manifold pressure. Given that the chamber pressure is typically >=20% less than the manifold pressure in constant pressure (traditional) rockets, this is where the performance increase can come from. That is, given the same turbomachinery, swapping out the thrust chamber with an RDE could increase your effective chamber pressure by a factor of 2. However, this also limits their applicability: as the pressure ratio, p_c/p_e, increases, the benefit of an higher chamber pressure decreases. This is apparent even with the above equation. I tend to think the sweet spot is for an OPR or NPR <= 20. So there isn't much of a pure performance benefit for rockets that already have a high pressure ratio - in-space propulsion, even main stage. That being said, they could still buy their way onto a launch vehicle because they have the potential to be smaller/lighter for equivalent performance.
Finally, I'll mention that no one has publicly demonstrated a performance benefit, or "pressure gain," with an RDE. I have no clue about proprietary / classified research.
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NASA Test Rare Supersonic Rocket Engine With Circular Combustion!
WCCFtech by Ramish Zafar Jan 29, 2023
NASA Generates More Than 4,000 Pounds Of Thrust With Rotating Detonation Rocket Engine (RDNE)
A typical rocket engine, like the one that powers NASA's Space Launch System (SLS) rocket or SpaceX's Falcon lineup, uses a standard combustion chamber to generate thrust. This chamber feeds the propellant (fuel) and oxidizer (combustive material) with high pressure into the chamber where they are lit up. The resulting thrust is then directed through a meticulously crafted nozzle - and the balance of the exhaust gasses and the products in the chamber (chamber pressure) is critical in determining whether the engine will work or if it will simply send the exhaust back into the tanks.
This process is called deflagration, a technical term in which the exhaust or the by-products of a combustion reaction travel slower than the speed of sound. In a similar vein, detonation is when the by-products travel faster than the speed of sound or supersonically. This lends them an added kick, as the gasses excite the particles of the medium they are traveling in. As a simple illustration, a Trinitrotoluene (TNT) explosion on Earth is a detonation, as the by-products of water, hydrogen, carbon monoxide and others travel faster than sound can in air. This also results in a characteristic shockwave that is observed with the explosions.
(https://cdn.wccftech.com/wp-content/uploads/2023/01/Rotating-Detonation-Engine-4-728x355.png)
A rotating detonation engine also uses the principle of detonation to build a self-sustaining pressure inside the combustion chamber, which leads to more fuel efficiency and higher power. In such an engine, the combustion products travel around inside a cylindrical combustor, or what is technically called an annulus. The shape of this combustor allows pressure waves from the detonation to revolve around the engine, with the waves 'chasing' themselves in a remarkable process. Their high speed leads to the waves covering tens of thousands of revolutions per second, and the process of detonation is better at converting the energy of fuel into thrust when compared to deflagration.
The aim of the tests, according to the space agency, was not to set new chamber pressure records. Instead, NASA aimed to evaluate whether the engine's build materials could withstand the high stresses of detonative combustion - particularly one used for rocket propulsion. These materials were built through 3D manufacturing, with the precise material being "NASA-developed copper-alloy GRCop-42," according to the space agency. The 4,000-pound thrust engine also successfully throttled and demonstrated internal ignition, with NASA now aiming to test a much more powerful 10,000-pound version.
More: https://wccftech.com/nasa-test-rare-supersonic-rocket-engine-with-circular-combustion/ (https://wccftech.com/nasa-test-rare-supersonic-rocket-engine-with-circular-combustion/)
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Rotating detonation engine
https://en.wikipedia.org/wiki/Rotating_detonation_engine (https://en.wikipedia.org/wiki/Rotating_detonation_engine)
A rotating detonation engine (RDE) is an engine using a form of pressure gain combustion, where one or more detonations continuously travel around an annular channel. Computational simulations and experimental results have shown that the RDE has potential in transport and other applications.
In detonative combustion, the results expand at supersonic speed. It is theoretically more efficient than conventional deflagrative combustion by as much as 25%. Such an efficiency gain would provide major fuel savings.
Disadvantages include instability and noise.
I have studied Pulse Detonation Engines(PDE), but not the Rotating Detonation Engines(RDE). I am close to completing my build of a PDE.
I just ordered a Shchelkin spiral. That should complete my build. I'll need to find a place I can operate it. Its already loud. Scares my dog.