You mention start-stop transients – that’s also something I was thinking about
regarding the discussion on PDEs – like how do you deal with the natural
inefficiencies you generally cop from these for PDEs or is there something
unique about PDEs that renders these not (as) relevant?
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of Robert Steinke
Sent: Friday, 31 January 2020 3:52 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Detonation velocity in nitrous/acetylene monopropellant
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/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
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
