The ultracentrifugal engine <http://halfwaytoanywhere.com/> Roger and I
worked on had the potential to provide aerospike thrust due to the shared
combustion chamber between multiple small nozzles. In the two-nozzle
minimalist engine, the tangential velocity of the engine's rotation would
need to be supersonic since the pressure from a nozzle's expansion would
travel only the diameter, while the nozzle had to travel the diameter times
pi in order to contain it. However, adding more nozzles would not be a
huge cost.
On Tue, Jul 14, 2015 at 12:08 PM, Brian Feeney <alaiadesign@xxxxxxxxx>
wrote:
I came across a 1990's Rocketdyne video on the development of their linear
aerospike engine covering development from the 1970's onward. You Tube -
search Aerospike - 4:49 secs
https://www.youtube.com/watch?v=EWf4iOMSPNc
A few things of interest:
Ignition of the 20 chamber engine is described as a "Combustion wave
ignition system" -- "Consisted of a central premixer which initiated a
detonation wave with simultaneous ignition of all thruster elements". That
means??
Two thoughts / questions: is that a small detonation of gaseous oxygen
hydrogen in a separate chamber with pipes guiding the detonation wave to
each chamber? Starting your engine with a bang!!
or as above but with hot combustion gases guided to each chamber through
piping - sort of a single igniter chamber with multiple outlets to ensure
single source ignition?
Something else I noted was the early thrust chambers were rectangular
"shoe" boxes (they show some of the construction) with the outlet on the
wide side of the box. Seemed to work for them - any combustion instability
with that geometry?
I noted in later engine development toward the end of the program that the
chambers were conventional circular tube with a square exit nozzle (radius
corners).
Thanks for comments.
Cheers
Brian Feeney
