[AR] Re: "Direct" Hydrogen Peroxide engines
- From: ignacio belieres <ignacio_belieres@xxxxxxxxxxx>
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Fri, 12 Aug 2016 16:38:34 -0300
In those detonations you described, what temperatures did the peroxide reach?
If you had a butane burner heating the peroxide then it was to be expected,
especially if it was under atmospheric conditions. Point is, other propellants
can also detonate if not handled properly, but that does not mean it will
automatically cato when used in a lpre.
Could you give me some sources on the claim that hypergolic engines lead to
chamber fragmentation? Sure if your ignition delay time is really long you
might have a problem, but most modern hypergolic mixtures (incl ours) have
delay times of around 14 ms or less. We are of course using the latter types of
mixtures you described.
Cheers,
IB
From: johndom@xxxxxxxxx
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
Date: Fri, 12 Aug 2016 15:53:42 +0200
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of ignacio belieres
Sent: vrijdag 12 augustus 2016 10:43
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines Yeah I would guess this
comes up ever so often, but I searched the archives and could only find so
little. Because too many emails were lost because of reorganisations. The
amount of literature on H2O2 with Google and USPTO is vast but rarely
useful.H2O2 can detonate for sure, but only in vapor compositions yes at
temperatures over 100 celsius AND in an enclosed environment. H2O2 is
surreptitious, stabilizer types, metal contact, temperature, pressure … ! It
can detonate in an open tube like hell. I survived detonations of 6 L 85 % H2O2
in an open glass Erlenmeyer (open air evaporation field tests from a save
distance) on a butane burner. Went whoosh without a bang but temp sensors had
melted and glass stoppers went orbital. My other test was open air boiling at
home with only 10 mL 90 %: that ended in a shocking bang like a shotgun and a
big stink. Wall scrubbing job ensued I would assume the environment inside even
a pre catalyzed biprop engine is harsher, but I havent heard of an explosion
ever happening like that, so it would seem unlikely for it to do so under
liquid-liquid injection. British Stentor HTP motors had their cat pack exhaust
inside the chamber. Simplest and I don’t think they ever exploded. Never read
as to why. We considered using a catalyst bed as many other successful
programmes have, but they tend to take a while to learn run well and are
somewhat expensive. Our experience with permanganate left a lot to be wished
for too so the only option is silver catalysts, which are tricky to use with
90% h2o2.
I mentioned hypergolic ignition because that is what we are aiming for. The
idea is to start the engine with a slug of a fuel that ignites with peroxide
and then switch to kerosene for better isp density. What do you think? It is
often mentioned (like on AR) hypergols are more prone to chamber fragmentation.
A sufficiently short ignition delay matters there. We tested an engine running
on our hypergolic mixture, a small one with only 500 N of thrust but its
objective wasnt raw thrust either. Do you mean ww2 hydrazine/Cu2+ or a
dissolved cat salt of the early 2000? jd From: johndom@xxxxxxxxx
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
Date: Fri, 12 Aug 2016 09:40:29 +0200This thread comes up every 5 years or so
on arocket, so was often discussed. Mixtures of gaseous or liquid H2O2 > 80 wt.
% have the nasty habit to detonate when heated and ignited. Add a fuel and the
detonation is worse of course. To have it deflagrate as a propellant you need
to pre-decompose the H2O2, monopropellant wise, in a controlled manner with a
catalyst bed in order to set free its oxygen as a gas, next spray a fuel in
this hot gas. Then it becomes a bipropellant. Ignition is not necessary as the
H2O2 decomposition gasses are typically hot enough to cause, say, kerosene
ignition. Google Black Arrow launcher. Also the once operational AR2-3 peroxide
bipropellant engine used a catalyst bed:
http://hydrogen-peroxide.us/uses-biprop-combustion/OSC-Peroxide-Propulsion-at-Turn-of-Century.pdf.
There are ways to pre-decompose H2O2 thermally which has been done
successfully. But so far it proved complicated compared to the simplicity of a
catalyst bed and never made it for launching anything. As far as I know. jd
From: arocket-bounce@xxxxxxxxxxxxx [
mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of ignacio belieres
Sent: vrijdag 12 augustus 2016 8:34
To: arocket@xxxxxxxxxxxxx
Subject: [AR] "Direct" Hydrogen Peroxide engines Hello everyone,
I have been lurking this list for quite a now, but not until
recently had I read the discussions on peroxide propulsion. Leaving the supply
problems aside, some have expressed doubts about being able to run a hydrogen
peroxide-hydrocarbon rocket engine in a direct mode without a catalyst bed.
Why is that? Could any of you name some projects where
it was attempted and found to be impossible or too difficult? I know a lot of
you have direct experience with this so I was hoping some of you might help me
clear some doubts. Perhaps a high characteristic length coupled with hypergolic
ignition could work for this application, or not.
Well, I can't wait to see what many of you have to say.
Cheers, IB
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