We weren't set up to do a proper detonation velocity measurement during
the ALASA program, but from the high-speed video of the rapid
disassemblies of the test stands, yeah, 1+ km/s. Good luck designing an
injector that can outrun that.
John Schilling
john.schilling@xxxxxxxxxxxxxx
(661) 718-0955
On 1/30/2020 8:52 PM, Robert Steinke wrote:
Well, I had a crazy idea, but it's not going to work. I thought, what if the nitrous/acetylene mixture were already going faster than the detonation velocity before you light it? Then the detonation would move relative to the motion of the gas, and it wouldn't be able to propagate upstream in the ground reference frame.
How would this work? You would start with a cold gas rocket and somehow trip the detonation at a point in the supersonic expansion bell once the gas is going fast enough. The detonation would boost the temperature and static pressure and then you would have a second stage expansion bell.
The problem is there's no way you are going to get a cold gas rocket to a sufficiently high exhaust velocity. Also, would the detonation propagate up the boundary layer that isn't supersonic? And you'd have to worry about what happens in the startup and shutdown transients. And it would be an inferior thermodynamic cycle, would that erase the performance advantage?
On Thu, Jan 30, 2020 at 7:13 PM Anthony Cesaroni <anthony@xxxxxxxxxxx <mailto:anthony@xxxxxxxxxxx>> wrote:
I ran it in LLNL Cheetah code a few years ago. It was around 6000
ft/sec IIRC correctly. The rest of the details don’t come to mind.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
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*From:* arocket-bounce@xxxxxxxxxxxxx
<mailto:arocket-bounce@xxxxxxxxxxxxx>
<arocket-bounce@xxxxxxxxxxxxx
<mailto:arocket-bounce@xxxxxxxxxxxxx>> *On Behalf Of *Robert Steinke
*Sent:* Thursday, January 30, 2020 10:04 PM
*To:* arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
*Subject:* [AR] Detonation velocity in nitrous/acetylene
monopropellant
If there's anyone on the list who knows, and can tell me, what is
the detonation propagation velocity in the recently discussed
nitrous/acetylene monopropellant? And is it a constant mach
number if the temperature of the propellant changes, or a constant
velocity, or something more complicated?
Thanks,
Bob
