Rotating Detonation Engine (RDE) -- Dynamics and Bifurcations
Why Hacker News recommends it
HN commenters recommend it for its fluid dynamics of detonation waves and its high-speed imaging of rotating pulses.
What it is
Nathan Kutz presents the spatio-temporal dynamics of rotating detonation rocket engines, including combustion fronts that behave like solitons. He shows a bifurcation analysis of a multiscale model that captures the main features.
Recommended by 2 HN commenters across 2 different months, 2021 to 2022.
What Hacker News said
Recommends flubloppoma · 2022-04 · on “No one knows why the most used spacecraft propulsion system works”
I think a better title would be "Hall Thrusters Understood So Well Better Instruments Needed to Measure the Friction of Quanta" - If something has momentum, it has mass. - If something isn't leaving an engine now, it's condensing. - Electromagnetic fields can recruit and organize a conductors' permissively and permeability. Hall Thrusters use electromagnetic confinement. - If there is a delay in exhaust, there is condensation. If there is condensation without a holding tank then there is a pulse holding the condensation. - Pulse waves require detonating fuel at the right time to feed the pulse and never feed the lull. Also, detonating is... different. Careful control of timing is needed to m
Recommends tofof · 2022-10 · on “Japan tests explosion-powered rocket for the first time in space (2021)”
Here's a video that presents the science behind rotating detonation engines; the article was pretty light on detail. This video is at the other end of the spectrum, clearly intended for other researchers in this domain. Or, if it's over your head (it was for me, at least while trying to wake up), you can still enjoy the pretty damn cool high speed imaging of the detonation waves in this type of engine. [this video]
Cites chrispeel · 2021-08 · on “Japan tests a rotary detonation engine in space, big increase in fuel efficiency”
Would an toroidal aerospike work with rotary detonation? :-) What sort of nozzles can one use with an RDE? I see that one can have multiple rotating pulses in an RDE [1]; I guess with some work the engine designer can control the number of pulses, is that right? Are there performance tradeoffs when deciding how many pulses to employ? What are they? If employing multiple pulses, does one want them rotating the same direction, or opposite directions? BTW, Scott Manley has an introductory video about RDEs [2]. [1] 5:50 in [this video] [2] [LINK]